Types of drug-testing programmes in the workplace


I. General features of testing programmes
II. Types of testing programmes
III. Implications and consequences of testing programmes
IV. Ways in which testing can be integrated into broad programmes
V. Infrastructure required for a testing programme
VI. Conclusions


Author: J. MRLAND
Pages: 83 to 113
Creation Date: 1993/01/01

Types of drug-testing programmes in the workplace

J. MRLAND Director, National Institute of Forensic Toxicology, Oslo, Norway


The article begins with a. discussion of the common features of drug-testing programmes. Regulations, procedures and methods for the collection of biological specimens, the subsequent handling and -analysis -of the specimens and the reporting of the interpreted results are all important aspects to be dealt with in testing programmes. Different types of testing are examined. Pre-employment testing is a popular type of screening but a number of other programmes exist, including post-accident, reasonable suspicion, post-treatment, random and voluntary testing programmes. The goals of these programmes range from improvement of employees' health, safety, quality of life in the workplace and productivity to reduction of drug misuse in society at large. Emphasis is placed on the need for scientific evaluation and on examining whether those goals have been achieved. In the absence of such evaluation, drug-testing programmes should be carried out with caution; some modifications of existing programmes are suggested.


The present paper provides a description of basic elements of programmes for the detection of a limited number of drugs and their metabolites or alcohol in biological samples.

The use of: drugs and alcohol can lead to changes in the composition of the body fluids. Such changes have, in particular, been reported after chronic use of alcohol [ 1] . Similar changes can, however, occur unrelated to the use of alcohol, and hence no alcohol-related biological marker or indicator can be taken as unequivocal evidence of alcohol intake, heavy alcohol consumption, alcohol misuse or alcoholism. Accordingly, such tests are not dealt with in the present paper. Since alcohol usually will remain detectable in biological samples for less than 24 hours after the last intake, and since it has no easily detectable metabolite, in contrast to most other drugs, alcohol would more easily escape detection, based upon the principles discussed in the present paper.

I. General features of testing programmes

All drug- and alcohol-testing programmes have common features such as the regulations, procedures and methods surrounding the collection of a biological specimen, the subsequent handling and analysis of the specimen and the production of an interpreted report. Important points in this regard are the underlying legal background, the agreements between the parties involved, the individual's informed consent, the correct selection of the biological medium to be analysed, the collection of information from the sample donor, for example, with respect to drug use; the sample collection procedures, the selection of sample containers, the shipment of the sample, the chain-of-custody procedures during sample collection, transport and handling in the analysing laboratory; the selection of drugs to be analysed, the process and methods for drug analysis, the reporting of results, the interpretation of analytical results, the interpretation of the report in relation to the individual in question (the medical review officer function); and the quality assurance and control of all the above points.

It is generally agreed that all precautions possible should be taken to guarantee and secure the best quality throughout the testing process. Accordingly, confirmatory drug analysis has become a required standard in almost any testing programme [ 2] , [ 3] , [ 4] . The reason for such demands is obviously the seriousness and consequences of the results of drug testing, which make false-positive results unacceptable.

It should be emphasized that the establishment and implementation of any testing programme require some kind of corporate drug and alcohol policy and the development of written statements concerning goals, and procedures to reach those goals. This process, which should involve both the employer and the workforce, is considered to be of great importance in its own right [ 5] .

A first step is to decide which drugs should be included in testing programmes. Drugs of interest can roughly be divided into two groups: (a) illegal drugs; and (b) legal (both prescribed and over-the-counter) drugs that have psychoactive properties, abuse potential or both. The second group, legal drugs, can be either misused or used as prescribed. Problems in the workplace are usually related to only the former of the two types of use, although the latter cannot always be considered fully uncomplicated. In addition there is alcohol. Alcohol escapes detection much more rapidly than most other drugs, but should nevertheless be kept in mind. Thus, testing programmes should aim at three different targets: alcohol, illegal drugs and other drugs. As will be seen, few testing programmes have taken this comprehensive approach.

To what extent can a worker be required to give information about the use of prescribed drugs? In a medical setting with no possibilities of negative sanctions as a consequence of a positive result, this question is hardly relevant. A different situation arises, however, when the result of, for example, urine analysis can lead to formal sanctions. As long as legal drugs are not included in the testing programme, few problems will arise, provided highly specific testing methods are used. In some cases, however, the consumption of legal drugs such as codeine and ethylmorphine can lead to the formation of the same metabolite (morphine) as the intake of heroin. In programmes that include testing for prescribed drugs with abuse potential such as barbiturates and benzodiazepines, information about the possible legal prescription of such drugs will have important implications for the final interpretation of the test results. In such cases, information about drug use by the individual is essential. Every testing programme of this type must therefore contain measures to obtain this type of information, while guarding the privacy and confidentiality of such information. Many testing programmes do not state clearly how such problems are handled, making their evaluation difficult. A medical review officer is, in most cases, the right person to deal with such problems. Close collaboration between the medical review officer and the laboratory may be required to solve complicated situations that may arise.

It is stated in various guidelines that the reporting of a positive drug finding in a biological specimen should be based upon a positive result by screening analysis as well as by confirmatory analysis [ 2] , [ 3] , [ 4] . Somewhat surprisingly, similar requirements do not seem to apply to the demonstration of the presence of alcohol by breath testing. This is inter- esting since it has been demonstrated that substances other than alcohol might yield false-positive results for alcohol-in breath tests using various instruments [ 6] , [ 7] , [ 8] . Since alcohol should, in principle, be regarded in the same way as other drugs in the workplace, it is difficult to find any rationale for this more lax attitude concerning confirmatory analysis in the case of alcohol.

In some test programmes the level of blood and breath alcohol is of critical importance in deciding whether action should be taken against the employee involved. In general, there are possible repercussions only if the concentration is above a certain level. Compared to blood alcohol measurement, breath alcohol determination shows much larger individual variation and is influenced by several factors, including breathing technique [ 8] , [ 9] and body temperature [ 10] . It has been shown that people with equal blood alcohol concentrations can have large variation with regard to their breath ethanol concentrations [ 11] , [ 12] . Thus, the question remains as to which concentration should be regarded as the correct alcohol concentration and which type of instrument and analytical principle should be used to determine the concentration.

It has been stated that the detection of a drug or its metabolites in urine only constitutes proof that the drug had been used once during a period preceding the test [ 3] . The result gives very limited information about when the intake took place and what dose was taken. It does not give information about the frequency or pattern of drug use, and cannot discern infrequent recreational use from drug abuse. Finally, a positive or negative drug finding in a urine sample does not give any reliable information about the influence of the drug at the time of sampling. All these uncertainties, which are highly relevant, have been pointed out repeatedly and should not be ignored. They have been mentioned to indicate shortcomings in urine -testing programmes, especially with regard to how testing can demonstrate drug influence and how its introduction could enhance workplace safety [ 13] .

There is a growing body of evidence indicating that the drug (and/or active metabolite) level in blood gives far more reliable information with regard to when the drug was used and to what extent the person was under its influence at the time of sampling [ 14] , [ 15] . With regard to influence or intoxication, it has been claimed that a correlation between blood concentration and effect has only been found for alcohol [ 13] . There are, however, few studies that have directly compared alcohol with other drugs with regard to the same measures of influence. Studies in which such a comparison has been made have not found profound differences between alcohol and other drugs with regard to the relationship between blood concentrations and the degree of influence [ 15] , [ 16] . At the present stage, it appears that blood-level determinations for alcohol and drugs are much more useful than urine determinations in indicating both influence and when the substance was last taken. The same applies to breath alcohol analysis, to the extent that such analysis reflects blood alcohol levels.

Other tests, for example, the measurement of psychomotor perfor- mance, have been recommended as alternatives to substance detection. Such tests have been claimed to be better for the evaluation of performance at a certain point in time [ 13] . Performance tests are, however, not without problems. Large individual differences in many tests require the establishment of individual baselines. Besides this, non-drug-induced, day-to-day variations have to be calculated for the various individuals to be tested. In addition, possible learning effects have to be taken into account. Finally, it is difficult to establish how relevant various psychomotor tests are in evaluating safety risk under workplace conditions.

II. Types of testing programmes

The different types of testing discussed in the present paper include:

  • Pre-employment testing;

  • Probable cause testing;

  • Reasonable suspicion testing;

  • Periodic testing;

  • Random testing;

  • Testing on return from treatment;

  • Testing related to transfer or promotion;

  • Voluntary testing.

A clear distinction exists between pre-employment testing programmes and other testing programmes. The use of such programmes have mostly been restricted to the United States of America and have been conducted according to guidelines set by the National Institute on Drug Abuse (NIDA) [ 2] . The guidelines mainly include the testing, by urine analysis, of a selection of illegal drugs commonly used in the United States; however' they also provide an option for testing prescription drugs. It should nevertheless be emphasized that the main experiences reported are based on programmes that, test mostly for illegal drugs, and not for abuse of alcohol or legal drugs.

A. Pre-employment testing

Pre-employment testing programmes, in which job applicants are tested, are the most popular type of drug-testing programme, offering the least liability to the employer [ 3] . Pre-employment testing is probably the most common and most widely accepted type of screening. Between 60 and 70 per cent of small businesses in one city in the eastern part of the United States and 80 per cent of the Fortune 500 companies that test for drugs are reported to include pre-employment screening in their programmes. A survey of federally regulated Canadian transportation companies with 100 or more employees revealed that approximately 15 per cent of the organizations performed 'Pre-employment testing [ 17] . Pre-employment testing is mandatory for commercial vessel personnel, according to the rules of the United States Coast Guard and Department of Transportation [ 18] . Those rules have been adopted in parts of the international maritime industry.

Data from various laboratories engaged in providing services to industry demonstrate an overall positive ratio of around 12 per cent in pre-employment testing [ 3] . An equal percentage was reported in a study on urine samples obtained during the pre-employment physical examination of hired employees at a large teaching hospital in the United States [ 19] . In that study, the results of the test had no consequences for the outcome of job applications. That was also the case in another study, performed on approximately 5,000 applicants for positions in the Boston Management Sectional Center of the United States Postal Service [ 20] . In that study, approximately 7.5 per cent of the samples were positive for cannabinoids, 2 per cent for cocaine and 2.5 per cent for other drugs. In yet another study of similar design, 10 per cent of all eligible job applicants tested positive for drugs at the time of their medical examination [ 21] .

Pre-employment testing has usually been performed with respect to illegal drugs. The efforts have been focused on cannabinoids, cocaine, amphetamines, opiates and phencyclidine. In some cases, other drugs like propoxyphene, barbiturates and benzodiazepines have been included in the screening procedure. Alcohol has seldom, if ever, been included. Urine has been the biological medium used.

It has been discussed whether pre-employment testing should encompass all job applicants. Usually this appears to be the rule. In some cases, however, pre-employment testing has been reserved for applicants for certain jobs within a company. The International Transport Workers' Federation (ITF) has stated that pre-employment testing should only be applied to employees in safety-sensitive positions [ 22] .

According to the NIDA comprehensive procedures for drug testing in the workplace [ 23] , the requirement of applicant testing should be indicated in vacancy announcements. Furthermore, the applicants should be informed about confidentiality protection. An applicant with a positive test result may be declined a final offer of employment [ 23] , but the procedures may allow the applicant to reapply after a certain period of time (e.g. six months).

Applicants should be informed if appointment to the position is contingent upon negative test results. The general impression is that the usual consequence of a positive urine test is refusal of employment. It is open to discussion whether an applicant should be given in advance information about when and where pre-employment testing will be performed. Many argue that, if that is done, drug-abusing applicants might adjust their drug intake and show up at a test with drug- free urine. One counter -argument is that, if a person is able to make such an adjustment, the degree of drug abuse must be light and should not lead to refusal of employment. ITF has stated that job applicants should be clearly warned in advance if pre-employment testing is to be carried out [ 22] . It is somewhat surprising that, in spite of advance notice of pre-employment testing, many applicants still have drug-positive urine test results. The reason for this might be severe drug dependence or lack of knowledge about how long after the last drug intake a person might continue to have positive test results.

Management has to decide at which stage in the hiring process pre- employment testing should be introduced. It could be used relatively early to screen out applicants before an interview takes place. It could be applied only to those who are the highest ranked applicants after the interviewing process and other pre-employment measures. Finally, pre- employment testing could be introduced as a last step before an offer is given.

In many cases, the pre-employment drug testing takes place during the pre-employment physical examination. While this is practical, it nevertheless requires the urine sample to be taken according to the regulations, procedures and methods governing the process. Usually a urine test for other purposes during physical examinations does not require similar precautions. Therefore, it might be useful to consider other occasions at which the pre-employment urine sample could be taken.

The chain - of - custody procedures, sample analysis, reporting results and review by the medical review officer for pre-employment testing should be similar to the chain for testing individuals already hired.

What is known about the impact of pre-employment testing programmes? To what extent are they able to achieve the general goals of any testing programme in the workplace? In general, it is assumed that, over a period of years, pre-employment drug testing will lead to a lower prevalence of drug use in the working population as drug users are screened out before being hired [ 3] .

In some studies, a more experimental approach to the problem has been applied. In those studies, the results of pre-employment urine drug testing were unknown to the applicant and the employer and, accordingly, test results had no bearing on employment. Subsequently, various measures related to job performance were monitored for a certain period after employment.

Studies from one group [ 20] , [ 24] of approximately 2,500 postal employees showed that, during the first year of work, those who had tested positive for cannabinoids in the original test had increased relative risks for turnover (1.56 times those who tested negative); accidents (1.55); injuries (1.85); disciplinary action (1.55); and absenteeism, (1.56). The relative risks were still high when they were evaluated two years later, though a slight reduction in risk was noticed. For those with positive cocaine tests, the relative risks after the first year of evaluation were as follows: turnover, 1.15; accidents, 1.59; injuries, 1.85; disciplinary action, 1.40; and absenteeism, 2.37. The figures did not decrease when the material was evaluated two years later [ 24] .

In a similar, blind, nationwide longitudinal study on approximately 5,500 job applicants conducted for the United States Postal Service, the relationships between the test results for illicit drugs and absenteeism, turnover, injuries and accidents on the job were evaluated [ 21] . After an average 1.3 years of employment, employees who had tested positive for illicit drugs had an elevated rate of absenteeism (1.59) and involuntary turnover (1.47). No significant associations were detected between drug- test results and measures of injury and accident occurrence [ 21] .

Another similar study involved a much smaller sample (n=180) consisting of employees hired at a large teaching hospital [ 19] . After a year of employment, comparisons of job performance, job retention, supervisory evaluations, and reasons for termination showed no difference between drug use and job performance. The study showed no statistically significant correlation with the findings in the other studies [ 20] , [ 21] , [ 24] .

Taken together, the studies give no clear answer as to the value of pre-employment testing. Although they indicate that there is a correlation between positive drug - test results during pre - employment screening and subsequent problems at work, it is difficult to make any generalizations based on the results. First of all, only illicit drugs have been screened for. A substantial body of literature suggests that alcohol abuse can be correlated with the abuse of other substances [ 25] . Alcoholics have poor employment outcome. It is uncertain whether pre-employment tests for alcohol use would have yielded different results with regard to job performance during the subsequent years.

Secondly, the studies were performed on population groups in which positive results would not have any bearing on recruitment. At the same time, ordinary pre-employment test programmes, requiring drug-free urine samples of applicants before they could be offered jobs, were operating elsewhere in the United States. That could indicate that the job applicants in question constituted a selected population.

Thirdly, the studies gave no advance warning to applicants that drug testing was going to take place. That could have led to a higher rate of positive samples than would have been found in a pre - employment programme in which such testing was announced in advance.

B. Probable cause testing

There are at least two categories of probable cause testing: one includes testing after accidents, near-misses and unsafe acts; the other includes testing when evidence of intoxication, impairment or other behavioural signs of problematic drug or alcohol use are witnessed. Some also include testing following poor job performance, while others would refer to that situation, as well as to all testing of the second category, as .reasonable suspicion testing" [ 23] .

Considering the first main category, which includes post-accident testing, some would require that testing be performed only if there is good reason to suspect impairment as a result of drug or alcohol abuse. A growing number of companies, however, require testing after all industrial accidents [ 26] . With that type of screening, no evidence is needed to indicate that the employees involved in the accident were impaired and subjective evaluation of each case is omitted. A possible outcome of that approach is that employees might be reluctant to report minor accidents and injuries for fear of being tested [ 27] . Some employers have attempted to deal with the problem by confining testing to accidents involving carelessness [ 26] . Automatic, post-accident testing might be acceptable to many employees as it might prevent, rumours about intoxication being a possible cause of an accident.

According to NIDA [ 23] , the intention of a programme for accident or unsafe practice testing is to provide a safe and secure work environment by having as an option the testing of any employee involved in an on- the-job accident or engaged in unsafe on-duty job-related activities. NIDA has also stated that it is important to specify conditions for accident and unsafe practice testing; thus, any employee involved in an on-the-job accident should be notified that testing will be initiated. It is also considered important to specify criteria for accident or unsafe practice testing; thus, testing may include but is not limited to death or personal injury requiring hospitalization or damage to property in excess of a predesignated amount. . In some countries, serious industrial accidents will more or less automatically be investigated by the police, who might order testing to reveal alcohol or drug impairment. Such action instituted by parties outside the workplace is, however, considered to be principally different from the test, programmes described here and will not be dealt with further in this paper.

The other category of probable cause testing involves testing employ- ees who show behavioural signs of problematic drug or alcohol use. One problem with such testing is that supervisors or others authorized to order the testing must focus on behavioural symptoms rather than work prob- lems. Because supervisors are usually not qualified to diagnose such symptoms, the practice could lead to singling out and labelling individuals who may or may not beef users [ 28] . Another criticism is that supervisors could use such testing to harass certain employees [ 22] . The latter problem could be circumvented, by a procedure recommended by Canadian authorities [ 29] , according to which:

"The grounds for testing will differ from case to case, but will generally pertain to an individual's behaviour or performance at the time. At least two people, one of whom is the supervisor, will need to conclude that there is sufficient reason to test."

Supervisors and employees can be instructed to recognize the signs of drug intoxication. This is not an easy task and there will always be the possibility of the supervisor making wrong decisions. It has been argued that this type of testing will meet limited criticism because of the fact that individuals are not tested unless sufficient evidence indicates that they are impaired by drugs or alcohol at work [ 26] , [ 30] . It has been stated that the written documentation of witnessed behaviour that corroborates test results is extremely important in such programmes. Osterloh and Becker [ 3] recommend that-a worker's supervisor should document his or her observations and should accompany to the test site the person who is under suspicion of drug use. It seems clear that the more objective the selection criteria for testing are, the more acceptable the testing process will appear to all parties involved. It might be possible to use performance tests [ 13] as a test criterion.

Probable cause testing of both categories described above are manda- tory after serious marine incidents [ 18] . This is also the case for safety- sensitive positions in Canadian transportation. Between 5 and 10 per cent of federally regulated Canadian transportation companies with more than 100 employees performed post-accident testing [ 17] . It is assumed that probable cause testing is being performed to an increasing extent, although firm evidence to support such an assumption is lacking.

Some studies have dealt with the results obtained from post- accident testing. Roman and Trice [ 31] concluded in 1972 that alcohol and alcoholism were of minor importance in workplace accidents compared with other accidents. Similar conclusions have been drawn by Linde in Denmark [ 32] . A French study demonstrated the presence of benzodiazepines in serum samples of 6 per cent of work accident victims [ 33] . There are, however, many more studies on drivers fatally injured in road accidents. Alcohol has been detected in 20 - 60 per cent and drugs in 7 - 30 per cent of cases involving such drivers [ 34] .

It is usually not stated explicitly which drugs are tested for in probable cause testing programmes. Since most of the experience in this area originates in the United States, it is most likely that the drugs specified by NIDA (illegal drugs) are tested for, and possibly benzodiazepines and barbiturates as well. In several programmes alcohol is also looked for. Urine is the usual medium for drug testing, while breath and/or blood samples have been taken for alcohol analysis. Most programmes in probable cause testing do not stress that the test should be performed as early as possible after the accident or other events leading to the test. The reason for this might be that usually only urine tests are carried out. As indicated earlier, a positive urine test result only proves that the drug was present in the urine. Urine drug concentrations do not necessarily correspond to pharmacological effects or drug impairment and give no information on the duration and severity of possible continual abuse. Blood drug (and alcohol) concentrations, however, give information about possible impairment, especially when evaluated together with results from an objective observation of the subject. In many countries, the combined evaluation of a clinical test (performance test) and blood drug concentrations constitutes the basis for expert witness statements in cases involving, for example, suspected driving under the influence of drugs [ 35] . It is, however, seldom that a similar practice is followed in cases of probable cause testing.

In principle, all employees should be subject to probable cause testing as such programmes should reflect a workplace policy of not tolerating drug or alcohol impairment while on duty. Some companies, however, have restricted such testing to persons in safety-sensitive positions. Post-accident testing also restricts probable cause testing to those who are in positions that are apt to be involved in accidents. This could constitute some degree of unfairness. It is obvious that impairment of people in positions responsible for strategic decisions, production secrets etc., might also put at risk a company's future and, in turn, its employees. It seems wise, therefore, for a company to check for possible impairment of all its employees.

The policy underlying probable cause testing programmes should be explained and made clear to all employees of the company in question. The company should also follow fair procedures for selecting situations for testing. The policy of the company should also include a description of the action to be taken when an employee refuses to submit to testing after a probable cause is documented. That should be part of the informed consent given by the employee when the testing practice was agreed upon.

As in other testing programmes, there is a spectrum of reactions to a positive result of probable cause testing. Such reactions might include a change of position within the company, leave of absence, intensified performance evaluation, resignation and termination [ 3] . With all of the above alternatives, counselling and treatment should be provided by a practitioner with experience in drug abuse and rehabilitation [ 3] . According to the NIDA comprehensive procedures [ 23] , an employee who tests positive should be referred to the employee assistance programme. If the employee occupies a sensitive position, he or she may be removed from that position and, at the discretion of the employer, may be returned to duty in that position if it is determined that such a return would not endanger the safety and security of others. Furthermore, it is stated that the employer may or may not take disciplinary action, which could include removal or termination, and that the severity of the action taken should depend on the circumstances of each case.

Probable cause testing contains, in contrast to other workplace testing programmes, a special problem concerning what action should be carried out in the period after the sample for drug or alcohol testing has been taken and before the test result becomes available. In practice, the action appears to vary from a leave of absence or change of position to no action.

There appear to be few if any studies that have specifically dealt with the effects of probable cause testing programmes.

C. Reasonable suspicion testing

Reasonable Suspicion testing includes testing of employees who exhibit lateness or a high degree of absenteeism or other suspect behaviour. There is no clear distinction between this type of testing and probable cause testing. It might be said that the grounds for testing on the basis of reasonable suspicion are less rigorous than those for probable cause testing. According to NIDA [ 23] , other situations are also referred to under the heading of reasonable suspicion testing. These are drug- related investigations, arrest or conviction of an employee, employee drug-test tampering, and information from reliable sources about drug abuse. In such cases, it is recommended that all information about the case should be gathered, including facts and circumstances leading to and supporting the suspicion. Furthermore, a written report should be prepared in such cases, detailing the basis for the suspicion. Then the employee should be notified and a test should be carried out.

Lateness or absenteeism might lead to reasonable suspicion testing; however, it appears that little has been published on how such a policy should be implemented. It might be possible to suggest that lateness or absenteeism of a certain magnitude should lead to a test. If so, that would have to be described in a drug policy statement or in some other written guidelines. Even when handled that way, some might feel it insulting should, for example, illness lead to drug testing. Complications could also arise if the illness has to be treated with drugs that are metabolized to morphine, giving rise to positive drug tests.. If, however, the decision to test is on a case-by-case basis, cases involving harassment by supervisors may arise.

Information on the extent to which reasonable suspicion testing programmes are used appears to be lacking, as is information on the frequen- cy of positive results when such testing is performed.

In principle, all types of drug and alcohol abuse should be considered possible causes for lateness and absenteeism [ 22] , [ 36] . This indicates that testing of this type should encompass both illegal and legal drugs, as well as alcohol. As discussed earlier, such testing would, however, be of limited value in detecting such problems, since it would have to be performed when the subject in question was back at work, more likely in a 'quiet phase" of an abuse problem.

It may be argued that such testing would be particularly useful for persons in safety-sensitive positions. If reasonable suspicion testing is to be undertaken in the workplace, it is important to have a clear policy on it, one which is accepted by the employees and which underlines the opportunity for rehabilitation that such testing might provide. It should also be indicated that the testing is part of a caring approach and that the consequences of a positive test result would emphasize counselling, treatment and rehabilitation more than disciplinary action. Consequently, it might be more pragmatic to consider such programmes in conjunction with medical check-ups.

D. Periodic testing

Periodic testing is usually found in programmes where employees are .tested for drugs or alcohol according to a predetermined timetable, usually during annual medical check-ups. Such programmes could also include testing upon return from lay-offs or lengthy illnesses. Under all these circumstances, the employees would usually be given advance notice of when tests would take place [ 22] . Testing of this type should most likely withstand most legal challenges. As with pre-employment testing, periodic testing enables drug users to avoid detection by abstaining from drugs for an appropriate period before the tests are administered [ 26] . Those who are more severely drug-dependent, however, will be less likely to abstain even when they know that. they will be tested. Periodic testing is included in the guidelines of the United States Coast Guard [ 18] , in many programmes that operate within the international maritime transport industry [ 22] , and in the strategy paper of -Transport Canada [ 29] . Periodic testing programmes are used by 10 per cent of federally regulated Canadian transport companies with more than 100 employees [ 17] . Most periodic testing programmes look for illegal drugs.

An important aspect of such testing programmes is their connection to medical examinations., A person applying to the United States Coast Guard for a licence or renewal of a licence is required to provide the results of a chemical test as part of a physical examination [ 18] . Transport Canada [ 29] has stated that periodic testing will be added to the medical examinations required for many employees in safety-sensitive positions and that the physicians designated to conduct the tests will make use of the employers' testing procedures and facilities. In this way, usage that might not be discovered in routine examination procedures could be identified. That statement is in sharp contrast with one that has been .released by one of the larger oil companies, according to which periodic testing has been shown to be of little value in detecting alcohol or drug abuse as it enables abusers to beat the system and has other negative consequences. If associated with periodic medical examinations, it may compromise the role of the company's medical adviser, jeopardize the value of the medical examination and lead to less effective medical service.

The latter, ethical aspect is debatable depending on the consequences of a positive test result. If the consequences are mostly of the counselling, treatment and rehabilitation type, it appears appropriate to link such a testing programme to physical -examinations. How effective such screening is, however, is a question to which there does not appear to be clear answers in the literature.

E. Random testing

Random testing involves testing employees without cause and notice. The employees are unaware of when testing will take place until the day of the test. Random testing includes either all or a certain number of employees. It has been emphasized that the randomization process should be real, so that all persons included in the test programme should have an equal chance of being tested. It is important that all persons within a programme are tested within a certain period of time [ 18] . Computer programmes or other objective techniques have been recommended for the randomization process. The means of selection should remain confidential [ 23] . Among the various types of testing programmes, random testing has generated the most resistance and controversy [ 26] , [ 30] . The negative factors mentioned include infringement of privacy [ 22] , discrimination, humiliation and promotion of insecurity, oppression and anxiety among employees, which in turn could reduce productivity. Random screening programmes have also been criticized for being inefficient and costly [ 3] . To identify, using random testing, most of the drug users in a population, urine specimens must be collected relatively frequently, considering the period of time that drugs may be present in the urine [ 3] . One positive factor that has been mentioned is that the possibility of an employee cheating the system is lower compared with other types of testing programmes. The strong deterrent effect of random testing has often been discussed [ 29] . From the point of view of the employer, random screening, unlike probable cause testing [ 28] , can be defended for not singling out individuals for suspicious behaviour or substandard performance in the workplace. Since each employee has an equal chance of being tested, individuals who are selected for a drug test are not at risk of being labelled by supervisors or fellow employees as possible drug users [ 22] . According to the NIDA comprehensive procedures for drug testing in the workplace [ 23] , the supervisor should explain to the employee that he or she is under no particular suspicion and that his or her name was selected randomly. The notification of selected individuals should be given with minimum advance notice (two hours are recommended). Random testing is recommended by the United States Coast Guard [ 18] , is used in the international maritime industry, is recommended by Transport Canada, and is used by a small percentage of Canadian federal transport companies [ 17] .

The percentage of samples with positive test results in random testing programmes will vary depending on the type of workplace and the type of drugs looked for. It is generally considered to be low, probably less than I per cent, depending on the group examined.

Usually, illegal drugs are the main focus of random testing pro- grammes. In some cases, alcohol and other drugs have been included. The United States Coast Guard regulations [ 18] state that only those crew members who are in safety-sensitive positions should be subject to random testing. This is also mentioned in guidelines for programmes conducted in other workplaces. In a case involving an oil company, random testing could only be justified for persons in environmentally sensitive and safety-sensitive positions and for designated management positions. There are a large number of people in such positions compared with those in strictly safety-sensitive positions. It is important that persons in positions designated for testing receive ample notice of being subject to random selection [ 23] .

Random testing should be based on a clear company drug policy. It contains many aspects of fairness that should be reinforced, for example, not exempting management from testing. It is somewhat difficult to see how this type of testing programme could be more offending than others - rather than the other way around. Obviously, the way the drug and alcohol policy is defined, as well as the way the testing programme is explained to employees, is critical to the acceptance of the programme. Programmes should have guidelines on the consequences of refusing testing after giving informed consent.

The consequences of a positive test result in a random test programme should also be described in the document on informed consent. The range of consequences are similar to those discussed in the subsection on probable cause testing.

Random testing in combination with medical examinations is not recommended, as it might confuse and jeopardize the integrity of the medical and health service in the workplace. The effect of random testing alone does not-appear to have been examined to any extent in a controlled study.

F. Testing on return from treatment

Testing after treatment and rehabilitation is discussed in the programme described by NIDA [ 23] . The goal of such a testing programme is to ensure that an employee has not had a relapse during or after treatment. Such a programme should include unannounced testing for a period of one year following the completion of a counselling, treatment or rehabilitation programme. It is suggested that testing should take place approximately once a month. The rationale behind such testing programmes appears to be the high relapse frequency among drug- and alcohol- dependent persons. Such testing programmes are reported to be used rather seldom by Canadian federal transport companies [ 17] .

Usually, the emphasis is on the detection of illegal drugs in such programmes, but in principle other drugs and alcohol could also be included. In this type of testing programme, the persons involved have been selected because of information about their past.

The information available about such programmes is limited. Emp- loyees should be informed that they will be subject to unannounced testing [ 23] , but what happens if they refuse to take part in such testing? Is informed consent a prerequisite to getting a job (or getting one back)? What should the consequences be of a positive test result in such programmes? In principle, both medical and/or disciplinary action might be taken, and the consequences should be stated in guidelines backed by the drug and alcohol policy of the workplace. In many respects, such programmes can be considered a category of random testing programmes that are conducted among a group of people who, as a result of past events, are considered to pose a certain risk.

G. Testing related to transfer or promotion

Testing related to transfer or promotion may be considered similar to pre-employment testing. The basis for such testing should be included in the company drug and alcohol policy. One reason for such testing could be the transfer of an employee to a. safety-sensitive or environ- mentally sensitive position. Otherwise the considerations concerning this type of testing programme are similar to those for pre-employment testing programmes. The only difference appears to be the fact that under this type of testing programme the person being tested is already an employee. What are the consequences of failing such a test? Do they include not ever being able to hold the new position? What implications does failing such a test have for the employees present position?

According to a Canadian survey [ 17] , only a few companies conduct such testing.

H. Voluntary testing

Voluntary testing is when an employee submits to testing although it is not a requirement. Such testing should provide employees with an opportunity to demonstrate their commitment to the goal of a drug-free workplace in their work setting and to set an example for other employees [ 23] . This can be arranged in such a way that an employee not in a position designed for random testing may volunteer to be included in a random testing programme. Voluntary testing can also help to eliminate suspicion of drug or alcohol abuse in certain situations [ 22] .

Voluntary testing could be used to test for drug or alcohol abuse, depending on the circumstances. The medium used (urine, blood, breath) would also depend on the circumstances. It should be possible to with- draw from a random testing pool at any time, except when an immediate test has been announced. The consequences of a positive test should be the same as if the test had been positive in that type of programme for which the person volunteered.

The circumstances under which a biological sample is given is critical in voluntary testing. A negative test result can only remain valid if the sampling and chain-of-custody procedures are beyond criticism.

III. Implications and consequences of testing programmes

The consequences for an employee who tests positive vary. The employee can be offered counselling, treatment and rehabilitation, organized inside or outside the workplace. Such activities might be organized within the framework of employee assistance programmes. Disciplinary action might follow a positive test result. 'Such action might involve a change of position within the company, leave of absence, close surveillance in the present position, !resignation or termination. How such measures are used, whether alone 'or in combination with others, might vary considerably from one workplace to another.

More long -term consequences for the employee will be dependent on the drug and alcohol policy of the company and on how drug testing is incorporated into other broad programmes. Those matters are dealt with in more detail in the next section.

How have drug-testing programmes contributed to goals for employees, employers, governments and society at large? Five different types of goals are often discussed: employees' health; employees' safety at work; job quality; productivity; and reduction of drug and alcohol use or misuse in society' All of these goals are important to society at large. The first four are the main interests of employers and the first two are most important to employees and unions.

The extent to which a testing programme can contribute to the achievement of the five goals will depend on different factors. Those factors include the consequences of positive test results for the employee, how well and how often drug testing is performed, which drugs are included in the programme, the drug and alcohol policy and the general climate in the workplace. It might appear quite reasonable that any drug-testing programme could contribute to the achievement of the goals.

Employee health might be influenced by the use of drugs and/or alcohol. It has been claimed that testing-programmes might prevent this. Testing programmes can be used to identify employees already using drugs and/or alcohol in a way that threatens their health, in order to facilitate their recovery.

Safety may be jeopardized on many different levels. The environment might be endangered as a result of an accident in the workplace. For example, public safety is related to the safety guidelines followed by transportation companies in carrying out their business. When an industrial accident happens, it may threaten the safety of both employees and the employer. Some empirical studies have concluded that drug users pose a greater risk of causing industrial accidents. In a study by Crouch and others [ 37] that relied on self -reported data on drug use, persons in the sample who reported drug use were five times more likely to have a reportable vehicle accident than non-drug-using persons in the sample, who had been matched according to age, sex, occupation, years of service and geographical location. According to the results from another study involving employed adults, drug users were nearly twice as likely to be involved in accidents on the job as persons who did not use drugs [ 38] . Similar results have been reported elsewhere [ 39] , [ 40] . Other evidence may suggest that problem drinkers are approximately 2-3 times more likely to be involved in industrial accidents than non-problem drinkers [ 36] , [ 38] , [ 41] . The claim is that drug- and alcohol-testing programmes will reduce or eliminate the chance that employees will be under the influence of substances in the workplace. Thus, the effects of drugs on employees' motor coordination, perceptual abilities, cognition and risk-taking behaviour will be absent in the work setting and, subsequently, the incidence of accidents will be reduced.

In competing industries and services, the integrity of the products may be of great importance to all persons who depend on those industries and services for their income. The quality of the work performed, in many cases, depends on the same factors that are related to job safety. The quality of the product, in a broad sense, may depend a lot on the employees' motor coordination, perceptual activities, cognition and responsibility. All these factors could be affected by the influence of drugs and/or alcohol. Testing programmes that reduce the incidence of such influences could therefore enhance the quality of the products.

Low productivity caused by absenteeism, tardiness and high turnover rates is a major problem in several workplaces. Some research has shown that the use of alcohol, cannabis, barbiturates and cocaine is related to indices of poor performance in the workplace [ 21] . A 15-fold increase in sick leave by drug users has been reported [ 42] . In a study by Pell and D'Alonzo [ 36] , problem drinkers were found to have approximately twice the rate of sickness absences compared with the control group. Again, the implementation of testing programmes in the workplace might reduce the use of drugs and alcohol, thereby increasing productivity.

In most countries, there is a clear policy on the elimination or reduction of illegal drug use, as well as on the reduction of alcohol consumption. Studies have shown that 70 per cent of all drug users are employed [ 22] . An even larger percentage of people who are problem drinkers or heavy consumers are probably working. It has been argued that workplace testing programmes provide a means to reduce drug use in society through both specific and general deterrence. Specific deterrence refers to identification of the individual user, followed by some type of interception leading to a situation where the apprehended user would be less likely to continue using drugs. General deterrence refers to the process whereby users who have not been identified are deterred by the threat of being identified.

Few studies have actually evaluated the consequences of the various testing programmes with regard to the above-mentioned goals and very few, if any, have examined separately the various types of testing programmes. The latter task is difficult since often many testing programmes operate more or less simultaneously within a workplace or a community. Some studies have therefore described the effects of drug testing more generally. It should be emphasized that most of the experience has been gained in the United States, where screening programmes have focused on five illegal drugs. This, together with the prevalence of drug use in the United States, should -be borne in mind when considering the results of other populations.

Some companies have noted reductions in the percentages of employees or job applicants who have tested positive over subsequent years of screening [ 43] , [ 44] . It is not known whether this reduction is directly linked to a decline in drug use. This outcome could also be interpreted to mean that employees have found ways of beating the test or that drug users seeking employment are less likely to apply for jobs that entail a screening programme [ 22] .

The prevalence of drug-positive urine tests among United States Navy personnel fell from 47 per cent in 1981 to 3 per cent in 1989. That development might indicate, but not prove, a reduction of drug abuse among that population as a consequence of drug-testing programmes [ 3] .

In a case involving a railway company, personal injuries declined after a drug-screening programme was introduced [ 45] . It is likely that the reduction resulted from improvements in the travel system and other safety measures [ 27] .

Although the results of several studies tentatively support the fact that drug users are at high risk for performance problems, those conclusions have been challenged because of flaws in the design and interpretation of the studies [ 46] .

According to a recent working paper by the International Labour Organisation (ILO) [ 22] , there might appear to be several reasons or objectives for employers to establish testing programmes, but empirical evidence from scientific studies is largely inconclusive as to whether those objectives are likely to be achieved.

Another recent ILO paper [ 5] concludes that the same uncertainties are present when the effect of assistance and prevention programmes including testing programmes are evaluated: "Unfortunately, much of the evaluation that has been completed of workplace programming has been anecdotal and non-experimental, allowing for little confidence in the results."

Thus, the present state appears to be that valid scientific documentation of the beneficial effects of any testing programme with regard to the goals for such programmes is generally lacking. There are, however, some indications that such programmes might be useful to the employees, the employer and society at large. 'The need for controlled studies is obvious, since the present situation is open to loosely founded speculation and guessing.

IV. Ways in which testing can be integrated into broad programmes

It is generally agreed that testing should constitute only a part of an integrated and comprehensive programme. It is therefore not surprising that, within the maritime industry, both the workers' organization and the employers' organization stress that programmes should contain assistance programmes for individuals [ 22] . Positive reporting of results of drug or alcohol testing that are followed by disciplinary measures only should therefore not constitute the rule. The essential main components of any comprehensive workplace alcohol and drug prevention and assistance pro - gramme seem to be (a) a written, well-communicated formal policy on drugs and alcohol; (b) the training of supervisors; (c) employee education; (d) employee assistance programmes; and-(e) drug and alcohol testing. Thorough evaluations demonstrating the beneficial effects of such integrated, broad programmes are generally lacking. The implementation of integrated programmes is often reported as positive.

The integration of testing programmes and individual assistance within a workplace occur along somewhat different lines. They can roughly be divided into two categories, referred to here as medical testing ("health" testing) and employer-organized testing ("control" testing). An extract of what appears to be the essential points of each is provided below:

A. Medical testing ("health" testing)

Medical testing ("health" testing) stresses the link between testing and the medical examination. The information from the testing goes to the physician, who combines this information with other clinical and laboratory information to reach his conclusions with regard to the employee's suitability for a certain position. The doctor also has the responsibility of referring the employee to treatment if needed.

The client's overall mental and physical health is, the focus of integrating testing and individual assistance. Of the testing programmes discussed earlier, periodic testing and testing on return from treatment often fall into this category. In. some instances, this also includes pre-employment testing and reasonable suspicion testing.

B. Employer-organized testing ("control" testing)

In. employer-organized testing ("control" testing), the enterprise determines the type(s) of testing programme as a part of its alcohol and drug prevention and assistance programme. If there is a positive test finding, it is reported back to the company by the medical review officer. The consequence of this report is primarily administrative, and it is usually followed by counselling, treatment and rehabilitation. This mixture of . medical and administrative action seems to, be included in most employee assistance programmes. Intensified testing can be used as part of this strategy. Deterrent factors of such programmes appear to be personal degradation, resignation or. termination.

The employer's need to control the workplace is the basis for this type of integrated testing. Most testing appears to be linked to this type of employer-determined programme. This applies in particular to probable cause testing, reasonable suspicion testing, random testing, testing related to transfer or promotion, and voluntary testing.

V. Infrastructure required for a testing programme

A. Skill level and related matters

It requires skill to explain why a drug and alcohol policy should. be part of company policy or to explain the rationale behind a testing programme.

Testing premises within a workplace require people with various medical skills. If urine is the medium of choice, the test station personnel should be able to secure and handle such samples. They should be able to perform simple, on - the - spot tests, measuring temperature, acidity, specific gravity etc. They should be able to provide precise information to sample donors and should know how to ask them questions about the use of legal drugs. The test station personnel should ensure that the employees sign the right documents, including a document certifying that the urine samples had been handled and secured correctly. The test station personnel are responsible for signing chain-of -custody documents and for shipping the samples to the laboratory. Depending on the circumstances, the test station personnel may need to be able to take blood samples and to operate testing equipment such as a Breathalyser.

The mandatory guidelines for federal workplace drug testing programmes (NIDA guidelines) [ 2] specify the skill levels needed to perform drug (and alcohol) analysis in a laboratory in the United States. The NIDA guidelines establish skill levels for laboratory management, supervisors and workers and set standards for instrumentation, analytical work, reporting, quality assurance and quality control. Similar guidelines exist for other laboratories performing similar work in the United States and in other countries. The skills required by the NIDA guidelines are linked to the urine analysis of five illegal drugs. Additional skills are required when other drugs and other biological media are involved in the analysis.

The medical review officer should be a physician with considerable knowledge of pharmacology, drug metabolism and pharmacokinetics, as well as drug and alcohol abuse. He or she should have some experience in laboratory work in order to communicate well with the analysing laboratory. In addition, the medical review officer is responsible for communicating to the employer reports on employee test results.

In summary, the highest skill levels are required by (a) the medical personnel collecting the information and the sample; (b) the analytical laboratory; and (c) the medical review officer interpreting the results for the employer. At those three stages - sample collection, sample analysis and interpretation of results - serious mistakes can made if the personnel involved lack the necessary competence or instruments. Such mistakes can easily lead to wrong results and, eventually, the punishment of innocent employees.

Thus, it is not advisable to accept standards that are below the level set by the NIDA guidelines. The possible consequences of erroneous reports are too serious to allow any deviation from the guidelines. Any such deviation might also have implications for costs, a matter that is discussed in the next subsection. If, in a developing or selected developing country, a decision has been made to implement testing programmes, the skill levels at the three stages discussed above will be critical to the quality of the final programme. In most developing and selected developing countries, the necessary expertise will be present but often not in the same abundance as in developed countries. Since it is difficult to accept any lowering of the standards discussed above, in a developing country, the analytical functions and the functions of the medical review officer may have to be combined in some way. That could be done if medical information on drug use is collected together with the sample and is shipped in confidentiality with the sample.

B. Costs

In general, the cost of running the testing component of a programme can be estimated quite accurately. The costs will differ from country to country, depending on price levels and salary levels.

The operation of a sample collection site includes the costs of renting the premises, as well as investments in equipment and instrumentation, containers, forms etc. The salaries of the medical personnel operating the sample collection unit will depend on their qualifications, which, again, will depend on which type of biological media they are to collect. The working hours lost by the employees providing samples should also be taken into consideration. In one study, the total costs of sample collection was estimated at nearly US$ 20 per sample [ 47] .

The mailing costs and, more importantly, the analytical costs is usually calculated as a certain sum per sample. That figure may vary greatly from one country to another. In the United States, analytical costs of US$ 20-30 per sample have been reported, that amount includes screening for five illegal drugs and the necessary confirmation analyses. If the screening programme is extended to include other drugs, the costs will increase, in particular if drugs are included that cannot be screened by immunological techniques.

The medical review officer is usually paid on an hourly basis. The hourly rate depends on the number of positive samples, the repertoire of drugs to be looked for and the qualifications of the medical review officer.

Most of the test results are negative. A United States congressional committee looking at screening in 38 federal agencies estimated the costs associated with each positive test of existing employees to be approximately US$ 77,000; an electronic manufacturer arrived at a cost of US$ 20,000 for each positive test. Where drug use is lower than in the United States, the cost per positive drug test is higher [ 22] .

Based on the pharmacokinetics of most drugs of abuse and the degree of sensitivity of most drug analyses, it can be calculated that every employee should be tested at least twice a week for 10 or more drugs to ensure abstinence from the usual drugs of abuse. To ensure abstinence from alcohol abuse, daily testing may be necessary. Such a test programme would probably cost at least 100 times as much as those currently in operation, which often conduct tests once a year. In programmes currently in operation, between 0.5 and I per cent of the tests are reported to yield positive results [ 22] . The costs per positive test in a more intensified programme are hard to estimate, but they are probably higher.

What conclusion should be drawn from high costs per positive test? Is it a positive indicator or a negative one? Are most of the samples negative because drug-testing programmes deter people from using drugs? Or is it possible that, despite large investments in testing, many drug users are not discovered by testing? In other words, is the actual figure for drug users among employees not 0.5 -1 per cent but, say, 10 -15 per cent? As long as the actual figures are missing, the costs per positive sample do not tell us much.

The question of cost- benefit has been dealt with in a recent paper by Zwerling, Ryan and Orav [ 47] . They based their calculations on the results of pre-employment screening of applicants to the United States Postal Service, whereby the results of the screening were not used in making employment decisions. The costs of additional absenteeism, accidents, injuries and, turnover for those who tested positive were calculated, together with the benefits gained if those people had not been hired. The cost of the screening plus the cost of recruiting and hiring an employee to replace one screened out were estimated. The study showed that pre- employment screening would have saved. US$ 162 per applicant hired. The model used was based on several assumptions, however. One was that the prevalence of drug use in the population screened was 12 per cent. Had it been 1 per cent, the programme would have lost money. Another assumption was that the total cost for screening and recruitment of replacements was US$ 49 per applicant hired. Finally, the average cost per accident was found to be US$ 169, a figure that could be much higher in many other industries. Thus, the conclusions reached are difficult to extrapolate outside the United States Postal Service. The results indicate, however, that pre-employment screening in. certain settings, in certain geographical regions, and for a certain group of drugs might yield more benefits than costs.

VI. Conclusions

There is general agreement that there is a need to reduce drug abuse and the use of alcohol in society.- It has been hoped that testing programmes in the workplace could contribute to the achievement of that goal. So far, however, there have been no scientific studies that have demonstrated that that is the case.

Some studies have dealt with the important question of determining what levels and patterns of drug and alcohol use threaten health, safety, job quality and productivity. Heavy use, as well as use during working hours, has been shown to be dangerous in this respect. The facts under- lying this statement, however, are not overwhelming. No studies appear to have shown that the infrequent use of alcohol and drugs is risky with regard to workplace performance and productivity. Positive test results from most screening studies cannot distinguish between frequent and infrequent use.

What are the positive effects of workplace testing programmes? The programmes are directed towards improving workers' health, increasing safety, improving job quality and increasing productivity. There are, however, almost no scientific data demonstrating that testing programmes have actually- achieved any of those goals.

Thus, there is an obvious demand for studies that demonstrate that separate or combined testing programmes can or cannot achieve such goals. This appears to be one of the most urgent tasks of the near future, the results of which should have a large impact on ongoing and planned testing programmes, Recent ILO papers have provided advice on how such research could be designed [ 5] ,. [ 22] . The results of such research will probably depend on, among other things, the substances that are looked for, the level of intensity that is used in the testing and the consequences of positive test results. Even after such studies have been carried out, however, it should be borne in mind that it also might become difficult to generalize about other countries with other prevalences of alcohol and drug use.

Another important point to remember is that most experience with drug-testing programmes has been gained in the United States, where there has been a broad national policy in support of testing. The implementation of testing programmes in countries not having such a policy might have quite different consequences. In many European countries, the national policy is -much more in support of other measures against alcohol use and abuse,. That will inevitably influence the climate of drug testing in the workplace.

As for immediate action, three main directions can be .,Chosen: (a) action could be initiated to suspend all testing until such time as firm evidence. of its usefulness is available; .(b) an attempt could be made to stop implementation of new programmes; and (c) some testing programmes that are demonstrating positive results could be supported and, perhaps simultaneously, some modifications could be introduced into those programmes. Some examples of the third alternative are provided below.

A prerequisite for all future. testing should first and foremost be a comprehensive drug, and alcohol policy. It should provide for the best procedures for 'sample collection, sample handling and shipping, chain of custody, drug and alcohol analysis, reporting, medical review officer functions and the careful consideration of final results by the company. Much harm could be caused by drawing the wrong conclusions or not devoting enough attention to such procedures.

Testing programmes could be divided into "health" and "control" testing. In a "health" test programme, the physician should act as the company's medical adviser, who knows the workplace and the qualifications required for- different jobs. Alcohol and drug testing should be part of an employee-physician relationship that is based on open-mindedness on both sides. The physician receives information, which might be checked by some kind of drug testing, and then informs the employee about it and, if agreed, conducts the test. Drug or alcohol problems are often denied for a long period; a positive test result might be the first step taken by an employee towards admitting that he or she has such a problem. Any information about drug use given to the physician as part of this process should be kept confidential. The laboratory analysing the test samples should send its reports to the physician. Thus, the employer should not be directly involved in the testing process. It should be the responsibility of medical personnel to ensure that proper testing procedures are followed. Using interviews with the employee and physical examinations, the physician should be able to obtain a general picture of the employee's health and suitability for the job in question. The physician's role in this connection should be that of helping and guiding the employee based on knowledge about his or her physical and mental state. The physician's opinion could, in some instances, lead to temporary (or permanent) exclusion from certain positions in the company. The p4ysician's recommendations could change over time if the health of the employee improves.

In the "health" test approach, testing would constitute only a part of the total health status that forms the basis of the physician's decision. The physician should try to initiate a programme for monitoring the employee's health by instituting an appropriate counselling and treatment programme followed by regular check-ups. Such initiatives could, if appropriate, include alcohol and drug testing.

Such a "health" test programme includes pre-employment testing, testing related to transfer or promotion, reasonable suspicion testing, periodic testing and testing upon return from treatment and rehabilitation.

In a 'control' test programme, the employer initiates the testing and obtains the interpreted test results. The employee is confronted with the results. In many respects, the situation resembles a meeting called after an employee has been observed impaired or intoxicated on duty. A physician or another medical staff member might become involved in diagnosing, classifying and evaluating any possible drug or alcohol problem. The role of the physician is more concentrated on the aspects related to alcohol or drug use. The physician is responsible for initiating, when appropriate, counselling, treatment and rehabilitation. The company is responsible for possible administrative action such as close surveillance in the present position, change of position within the company or leave of absence. Thus, the consequences of such behaviour should be clearly visible to all other employees.

In the future, "control" test programmes should only include probable cause testing, which might be referred to as "safety testing". Such testing could be performed after any accident of a certain magnitude involving behaviour symptomatic of drug or alcohol abuse. It could also be exten- ded to include other contexts, such as certain safety-sensitive jobs. The type of jobs to be subjected to "safety testing" should be determined beforehand. A decision should be reached on how such testing could be randomized. The focus should be on safety risks related to impairment, which are the most important issues. Until more is known about the effect of testing on other aspects, impairment while on duty could constitute. the primary focus. It is well known, for example, that drug and alcohol impairment is an important risk factor in road traffic.

The preferred test medium used should be blood (breath testing should be used as a screening test if only alcohol abuse is being checked). The results of blood testing are of greater interest than urine testing from the point of view of evaluating impairment and the time of drug and alcohol intake. The collection of the sample could be accompanied by the formulation of a written report on behavioural symptoms signed by the supervisor and a neutral medical officer (not the employee's physician or the company physician). If possible, a performance test should also be conducted by the neutral medical officer. The test results and the laboratory results should go through a medical review officer experienced in handling such cases.

Thus, more studies are needed to determine the impact of ongoing programmes. In the meantime, discussion could focus on introducing modifications into existing programmes.



H. Stibler, "Carbohydrate-deficient transferrin in serum: a new marker of potentially harmful alcohol consumption reviewed", Clinical Chemistry, vol. 37, No. 12 (1991), pp. 2029-2037.


National Institute on Drug Abuse, 'Mandatory guidelines for federal workplace drug testing programs; final guidelines", Federal Register, vol. 54, No. 69 (1988), pp. 11970-11988.


J. D. Osterloh and C. E. Becker, "Chemical dependency and drug testing in the workplace", Western Journal of Medicine, vol. 152, No. 5 (1990), pp. 506-513.


A. Christophersen and J. Morland, 'Legal aspects important for drugs of abuse testing', Proceedings of First International Symposium on Current Issues of Drug Abuse Testing, J. Segura and R. de la Torre, eds. (Boca Raton, Florida, CRC Press, 1992), pp. 9-14.


Proceedings of International Information Exchange on-Drugs in the Workplace (Geneva, International Labour Office, 1991), pp. I- 179.


W. Giguire, D. Lewis and R. E. Basett, "More -proof that solvents cause false high readings on intoxilyzers", DWI Journal vol. 6, No. 4 (1991), pp. 5-6.


W. Frankvoort, J.A.G. Mulder and W. Neuteboom, 'The laboratory testing of evidential breath-testing machines', Forensic Science International, vol. 35, No. 1 (1987),t pp. 27-43.


P. T. Normann and others, 'Measurement of ethanol by alkomat breath analyzer: chemical specificity and the influence of lung function, breath technique and environmental temper8ittire", Blutalkohol, vol. 25' No. 3 (1988), pp. 153-162.


J.A.G. Mulder and W. Neuteboom, "The effects of hypo- And hyper- ventilation on breath alcohol measurements", Blutalkohol , vol. 24, No. 5 (1987), pp. 341-347.


G. R. Fox and J.S. Hayward, "Effect of hyperthermia on breath-alcohol analysis", Journal of Forensic Sciences, vol. 34, No. 4 (1989), pp.836-841.


U. Loos and U. Heifer, "The time courses of the alcohol concentrations in breath and blood and of some alcohol effects", Blutalkohol, vol. 16, No. 5 (1979), pp. 321-338.


A. W. Jones and others, "Measuring ethanol in blood and breath for legal purposes: variability between laboratories and between breath-test instruments", Clinical Chemistry, vol. 38, No. 5 (1992), pp.743-747.


Ontario Law Reform Commission, Report on Drug and Alcohol Testing in the:Workplace (Toronto, Queen's Printer for Ontario, 1992)t pp. 1-121.


A. Ohlsson and others, "Plasma delta-9-tetrahydrocannabinol concentrations and clinical effects after oral and intravenous administration and smoking", Clinical Pharmacology and Therapeutics, vol. 28, No. 3 (1980), pp. 409-416.


J. Ingum and others, "Relationship between drug plasma concentrations and psychomotor performance after single doses of ethanol and benzodiazepines", Psychopharmacology, vol. 107, No. 1 (1992), pp. 11 - 17.


J.F.W. Haffner and others, "Mental and psychomotor effects of diazepam and ethanol", Acta Pharmacologica et Toxicologica, vol. 32, Nos.3-4 (1973), pp. 161-178.


S. Macdonald and S. Dooley, 'The nature and extent of EAP's and drug screening programs in Canadian transportation companies", Employee Assistance Quarterly, vol. 6, 1991, pp. 23-40.


United States of America, Coast Guard, Department of Transportation, "Programs for chemical drugs, and alcohol testing of commercial vessel personnel: final rule". Federal Register, vol. 53, No. 224 (1988), pp. 47064-47082.


D.C. Parish, "Relation of the pre-employment drug testing results to employment status: a one-year follow-up", Journal of General International Medicine, vol. 4, No. 1 (1989), pp. 44-47.


C. Zwerling, J. Ryan and E. J. Orav, "The efficacy of pre-employment drug screening for marijuana and cocaine in predicting employment outcome", Journal of the American Medical Association, vol. 264, No. 20 (1990), pp. 2639-2643.


J. Normand, S. D. Salyard and J. J. Mahoney, "An evaluation of pre - employment drug testing", Journal of Applied Psychology, vol. 75, No. 6 (1990), pp. 629-639.


International Labour Organisation, "Working paper on drug and alcohol screening issues in the maritime industry", Interregional Tripartite Meeting of Experts on Drug and Alcohol in the Maritime Industry, Geneva, 29 September-2 October 1992.


National Institute on Drug Abuse, Comprehensive Procedures for Drug Testing in the Workplace, DHHS Publication No. (ADM) 91-1731, 1991, pp. 1-19.


J. Ryan, C. Zwerling and M. Jones, "The effectiveness of pre- employment drug screening in the prediction of employment outcome", Journal of Occupational Medicine, vol. 34, No. 11 (1992), pp.1057-1063.


E. Kaufman, "The relationship of alcoholism and alcohol abuse to the abuse of other drugs", American Journal of Drug and Alcohol Abuse, vol. 9, No. 1 (1982), pp. 1-17.


R. P. Decresce and others, Drug Testing in the Workplace (Chicago, American Society of Clinical Pathologists, 1989).


J. P. Jones, "Drug testing did not reduce Southern Pacific's accident rate", Forensic Urine Drug Testing, June 1990, pp. 2-4.


R. L. Dupont, "Mandatory random testing needs to be undertaken at the worksite", Controversies in the Addiction Field (Dubuque, Iowa, Kendall/Hunt Publishing, 1990), vol. 1, pp. 105-111.


Privacy Commissioner of Canada, Drug Testing and Privacy (Ottawa, Minister of Supply and Services Canada, 1990), pp. 1-78.


L. Stennett-Brewer, "Employer drug testing: legal issues; interview with Karen Hawley Henry", Employee Assistance Quarterly, vol. 4, No. 1 (1988), pp. 57-70.


P. M. Roman and H. M. Trice, "Deviance and work: the influence of alcohol and drugs on job behaviors", Review of Environment and Health, vol. 1, No. 1 ( 1972), pp. 7-51.


F. Linde, "Alkohol og ulykkestilfaelde", Ugeskrift for Loeger (Copenhagen), vol. 148, No. 37 (1986), pp. 2363-2367.


C. Girre and others, "Detection of blood benzodiazepines in injured people: Relationship with alcoholism", Drug and Alcohol Dependence, vol. 21, No. 1 (1988), pp. 61-65.


H. Gjerde, K. M. Beylich and J. Morland, "Incidence of alcohol and drugs in fatally injured car drivers in Norway", Accident Analysis and Prevention, vol. 25, No. 4 (1993), pp. 479-483.


A. Bjoreneboe and others, "A retrospective study of drugged driving in Norway", Forensic Science International, vol. 33, No. 4 (1987), pp. 243-251.


S. Pell and C. D'Alonzo, "Sickness absenteeism of alcoholics", Journal of Occupational Medicine, vol. 12, No. 6 (1970), pp. 198-210.


D. Crouch and others, "Critical evaluation of the Utah Power and Light Company's substance abuse management program: absenteeism, accidents and costs", Drugs in the Workplace: Research Evaluation Data, National Institute on Drug Abuse Monograph Series No. 91 (Rockville, Maryland, 1989).


R. Hingson, R. Lederman and D. Walsh, "Employee drinking patterns and accident injury: a study of four New England states", Journal of Studies on Alcohol, vol. 46, No. 4 (1985), pp. 298-303.


Establishing a Drug-Free Workplace, Federal Personnel Manual (Washington, D.C., United States Office of Personnel Management, 1986).


P. B. Bensinger, "Drugs in the workplace", Psychiatric Letters, vol. 4, No. 1 (1986), pp. 39-44.


N. A. Maxwell and others, "Study of absenteeism, accidents and sickness payments in problem drinkers in one industry", Quarterly Journal Studies on Alcohol, vol. 20, No. 2 (1959), pp. 302-312.


J. D. Quayle, "American productivity: the devastating effect of alcoholism and drug abuse", American Psychologist, vol. 38, No. 4 (1983), pp. 454-458.


S. B. Needleman and R. W. Romberg, "Comparison of drug abuse in different military populations", Journal of Forensic Sciences, vol. 34, No. 4 (1989), pp. 848-857.


R. E. Willette, "Drug Testing Programs", Urine Testing for Drugs of Abuse, National Institute on Drug Abuse Monograph Series No. 73 (Rockville, Maryland, 1986).


R. Taggart, "Results of the drug testing program at Southern Pacific Railroad", Drugs in the Workplace: Research and Evaluation Data, National Institute on Drug Abuse Monograph Series No. 91 (Rockville, Maryland, 1989).


J. Horgan, "Your analysis is faulty", New Republic, 1990, pp. 1-3.


C. Zwerling, J. Ryan and E. J. Orav, "Costs and benefits of pre- employment drug screening", Journal of the American Medical Association, vol. 267, No. 1 (1992), pp. 91-93.