Urine drug screening and the family physician

Urine drug screening and the family physician

Andrew E. Floren

Urine drug screening has become increasingly common in the effort to cope with the growing drug-abuse problem in corporate America. An estimated 13 million persons in this country use illicit drugs. Of these, 10 million use marijuana and 1.6 million use cocaine.[1] Each year, drug-related absenteeism and medical expenses cost businesses approximately $60 billion, or 3 percent of their total payroll expenses.[2] In a survey of drug abusers seeking treatment, approximately 75 percent reported using drugs at work and 18 percent admitted stealing from fellow employees to support a drug habit.[3]

In addition to direct medical costs, occupational drug use causes an increased potential for accidents. A recent Canadian study[4] showed that 8.5 percent of workplace fatalities involved persons who tested positive for marijuana use.

A relationship exists between these costs and urine drug screening results. Persons who test positive for marijuana on a pre-employment screen have a 55 percent higher accident rate, an 85 percent higher injury rate and a 78 percent higher absenteeism rate than those who test negative. Cocaine users have a 145 percent higher absenteeism rate and an 85 percent higher injury rate than persons who do not use cocaine.[5,6] Drug screening programs have been credited with helping to reduce the rate of occupational drug use. In 1980, the combined U.S. military services reported a 27 percent drug-use rate. After the services instituted a urine drug-screening policy in 1982, the rate dropped to its current level of 5.3 percent (as shown by urine drug screening results).[7]

Legal Background

Occupational drug screening is a matter of controversy. Opponents of urine drug screening point out that a positive urine drug screen provides no information about the employee’s pattern of drug use or level of functional impairment at a given time.[2,8,9] Opponents also argue that such screening violates employee confidentiality and invades privacy.[5,10] Despite these concerns, however, a 1986 presidential order,[11] as well as regulations of the U.S. Department of Transportation (DOT),[12] the Nuclear Regulatory Commission (NRC) and the Department of Defense (DOD), mandates urine drug screening for all federal employees and for most private employees who work for these agencies.

The Americans with Disabilities Act permits urine drug screening.[13] Current illegal drug use is not legally considered a disability; however, the act protects former drug abusers, persons undergoing drug rehabilitation and persons erroneously believed to use drugs.

Role of the Family Physician

Occupational urine drug screening is a growing reality of American life. Because of the shortage of specialists in occupational medicine,[14] family physicians may want to investigate occupational urine drug screening and decide whether they wish to become involved in the process and, if so, at what level. Currently, formal credentials are not required, but they are likely to become more important in the future.

The family physician may be involved in occupational urine drug testing at two levels (Table 1): in specimen collection or in the role of medical review officer (MRO). Many family physicians already provide urine collection services for employers. Others fulfill MRO functions by reviewing urine drug screening results.


Occupational Urine Drug Screening

Activities and Responsibilities

Urine collection

Ensure proper identification

Ensure contaminant-free specimen

Ensure specimen integrity

Initiate chain-of-custody form

Review of results (duties of medical review officer)

Receive results

Review chain-of-custody form

Reject improper specimens

Review positive results

Report verified positive and negative results to


Reopen case to examine new evidence as needed

May recommend rehabilitation program

May supervise return-to-work testing schedule

and results

Derived from Swotinsky and Chase.[8]

This article reviews the two levels of physician involvement in occupational urine drug screening and provides references for reliable office collection of specimens and interpretation of results. DOT, NRC, DOD and Department of Health and Human Services regulated tests require specific, detailed provisions and should not be performed unless references are obtained and compliance with guidelines is assured. Reference guides (Table 2) and specific articles[2,8-10] are essential supplements to this article for any physician formally working in occupational urine drug screening.


The physician involved in occupational urine drug screening serves as an agent of the employer.[10] All interactions with the patient, laboratory, pharmacy and other persons or agencies should be charted, and the forensic nature of the activity should always be kept in mind.

The MRO role may invite litigation if an employee loses a job or encounters employment problems because of a positive urine drug screening result. The physician should carefully consider confidentiality, charting and office policies before undertaking MRO duties. Some physicians may be uncomfortable with this situation. Both practical and personal issues should be considered before a physician becomes involved in occupational urine drug testing. The MRO serves as an adviser to the employer and should not be viewed as a policeman. The physician-patient relationship, however, differs from that in conventional patient care.

Urine Collection

Proper urine collection is not simple. Two types of collection currently exist: one type is mandated by the DOT, NRC and DOD guidelines, and the other type is not federally mandated. Most urine drug collection work is undertaken for nonmandated employers.

Federally mandated examinations require specific procedures for ensuring accurate identification of the employee, proper obtainment and sealing of the specimen, and initiation of a legally acceptable chain of custody.[15,16]

Nonmandated tests may not require such attention to detail but, because an employee’s livelihood and reputation may be at stake, it seems prudent to follow the more stringent federal guidelines. Medicolegal difficulties may result if an employee disputes a positive urine drug screen result on the grounds that the screening did not follow federal guidelines, even if those guidelines were not required; therefore, this article outlines the procedures currently mandated by federal guidelines. Physicians should familiarize themselves with the DOT Drug Testing Procedures Handbook (Table 2) before they begin urine collection. These guidelines are currently under revision and will change within one or two years.

The goal of urine collection is to obtain a specimen that is properly identified and tamper-free. Tampering is an attempt to alter test results by manipulating the specimen. Manipulation may include the addition of various agents to the urine (e.g., peroxide, bleach, detergent) in an attempt to disrupt the testing methodology, or the addition of water in an effort to dilute the urine concentration of a drug. Tampering also includes attempts to submit another person’s urine as one’s own. Some signs of tampering are obvious, such as a strong bleach smell from the specimen. Any signs of tampering should be noted, and a repeat specimen should be submitted for testing along with the original. The repeat specimen should be obtained under direct observation.

Several steps are necessary to ensure submission of a forensically acceptable specimen for examination. Regulations may require that a “split sample” (a second container of the same specimen that is stored for reanalysis) also be collected.


The collection area should contain a private urination room, sink and writing surface. The urination room’s faucets (if any) and toilet holding tank should be secured with tape or by shutting off the water to prevent the employee from diluting the specimen with water. A bluing agent should be added to the toilet water to reveal attempted dilution of the specimen with toilet water. The employee should have no access to any other water or cleaning agents during urine collection. Office personnel should be trained in the proper procedures for urine collection. Appropriate materials include a sealed specimen container, a chain-of-custody form, packing materials, a urine temperature measuring device and items required for specific tests.


Photographic identification of the employee is preferred, but the employee can be identified in person by a company representative. If either of these are not possible, the urine collection should not continue. The employee should sign an information release specific for urine drug testing (Figure 1). Should the employee refuse to sign the release, the company should be notified, and the urine collection should not proceed.


The chain-of-custody form should be filled out carefully. This form is a forensic tool necessary to ensure the integrity of the urine specimen. The form should be signed by the collector, certifying that he or she collected the urine properly. The form then accompanies the specimen and is signed by each person who handles the specimen, certifying that each signer always had control of the specimen.


The employee should be instructed (and observed) to wash and dry his or her hands to ensure removal of any contaminants under the fingernails. The employee should also remove any outer garment, such as a coat, jacket or hat, to make it more difficult to hide another person’s urine. It is not necessary for the employee to completely disrobe; however, if a subsequent physical examination is to be performed, the employee may provide the specimen while wearing an examination gown.


The employee should be instructed to void at least 60 mL of urine. Clean-catch or midstream collection is unnecessary. Direct observation of the actual voiding is unnecessary unless reasonable cause exists to watch for tampering. Reasonable cause would include the following situations: notification from the company that this is a reasonable-cause screening; obvious tampering (for example, bluing in the urine); or a urine temperature measured within four minutes that is not within 32.5[degrees] to 377[degrees]C (90.5[degrees] to 99.8[degrees]F) and the employee refuses to allow an oral temperature to be taken, or the oral temperature differs by 1.0[degrees]C (1.8[degrees]F) from the urine temperature.

If tampering occurs, it should be documented and a second urine specimen collected under direct observation. Observation, if necessary, should be performed by a person of the same sex. If the employee cannot provide the requisite amount of urine, he or she should be instructed to drink fluid–240 mL every 15 minutes, up to 1 L[16,17]–and wait for up to eight hours. New guidelines will likely shorten this to two hours and limit the fluid amount. If the employee still cannot provide a specimen, the company should be called for further direction.


The temperature of the urine specimen is taken within four minutes of urination to ensure an accurate reading. The urine temperature and any other unusual findings should be noted on the chain-of-custody form. The urine specimen should remain visible to the collector and the employee at all times until it is appropriately sealed. Specific steps for sealing and labeling the specimen depend on the type of urine drug screen being collected (i.e., mandated guidelines or not) and the kit manufacturer’s recommendations.


The chain-of-custody form should be completed. If the employee refuses to sign the form, this refusal should be documented (remember that the employee has already signed an information release).


The sealed specimen should be kept in a secure place with controlled access until it is shipped to the laboratory.


Urine in excess of the 60 mL needed for screening is poured into a second container. The split sample is treated the same way as the original sample. It is stored at the laboratory until needed, if ever. It is likely that new DOT guidelines will require split specimens on all mandated drug collections and also change the amount of urine required in each sample.

Current DOT regulations allow screening for only five drugs: marijuana, cocaine, amphetamines, opiates and phencyclidine (PCP). If other drugs are to be sought, a second urine specimen should be obtained. However, if an occupational accident or incident prompts the collection, screening for any drug is permissible, even under DOT guidelines.

Review of the Results

An MRO should review the test results to determine whether positive findings actually indicate illegal drug use. Screening tests may be positive as a result of prescription drug use or other ingested agents.[8,10,15,16,18] When results are negative in federally mandated examinations, MRO administrative review is currently required only to assure that proper testing procedure was followed.

The MRO is a licensed physician with a knowledge of substance abuse disorders.[8,12] Specific training or certification is not currently required but is soon likely to be required for federally mandated examinations. The MRO must be familiar with the properties, pharmacokinetics, metabolism, legal use and other aspects of a wide range of drugs. The MRO must also be expert in regulations and possible legal causes of a positive test.[10] The MRO protects the employee against false accusations from an invalid test result and increases the reliability of the drug screening program for the employer. The physician who participates in occupational urine drug screening should be familiar with rehabilitation resources for drug abusers.[10]

Rehabilitation is often accomplished through the company’s Employee Assistance Program (EAP). An EAP helps identify employees with personal problems and motivates them to seek and accept diagnosis and appropriate help.[2] Thus, the MRO should become familiar with the company’s EAP, as well as appropriate rehabilitation facilities.

Laboratory Tests

Several types of tests are available for illicit drugs.[9] A screening test identifies specimens most likely to contain the substances sought. Positive specimens are retested, using a confirmatory method. A specimen must test positive by both methods to be considered a confirmed positive specimen. Gas chromatography-mass spectrometry is currently the only acceptable confirmatory method.[19]

A positive test on screening examination that is not confirmed has a 35 percent chance of being a false-positive result.[8] Specimens identified as positive both on initial screening and on analysis with gas chromatography-mass spectrometry are considered forensically acceptable,[9] although some small controversy exists over this issue.[20]

False-positive results on both tests, while rare, can be caused by such factors as improper testing methods and cross-reactivity. It is recommended (and required in federally mandated examinations) that the laboratory be certified by the Substance Abuse and Mental Health Service Administration (formerly the National Institute on Drug Abuse), to ensure the most reliable test methods and in-depth investigation and remediation of false-positive results.

Interpreting Urine Drug Screening Results

The most important task for the MRO is to correctly interpret positive results of urine drug screening. The MRO must determine whether a drug is in the urine for a legitimate reason.

Many good documents can help the MRO determine this,[9,15,16,21] but no document completely covers all of the issues or possibilities. Simply reading published materials is not adequate preparation for performing MRO duties. Any physician who wishes to perform MRO duties should attend a seminar that teaches the activities more completely. Table 2 lists three seminar resources for the family physician undertaking MRO duties.

Because federal regulations are currently being revised and drug testing information changes frequently, the MRO also must acquire frequent updates. MRO certification is not currently required; however, some organizations do offer certification, and it is likely to be required for federal programs at some time.

The author thanks Jim Small, M.D., M.P.H., and the physicians of WorkMed Occupational Health Network, Tulsa, Okla., for assistance, as well as Brenda K. Richards for manuscript preparation.


[1.] National household survey on drug abuse, 1990. National Institute on Drug Abuse, Division of Epidemiology and Prevention Research. Rockville, Md.: Alcohol, Drug Abuse, and Mental Health Administration, 1991; DHHS publication no. (ADM) 91-1788. [2.] Seymour RB, Smith DE. Identifying and responding to drug abuse in the workplace: an overview. J Psychoactive Drugs 1990;22:383-405. [3.] Drug free workplace [Editorial]. Am Fam Physician 1988;38(5):80,82. [4.] Alleyne BC, Stuart P, Copes R. Alcohol and other drug use in occupational fatalities. J Occup Med 1991;33:496-500. [5.] Zwerling C, Ryan J, Orav EJ. The efficacy of preemployment drug screening for marijuana and cocaine in predicting employment outcome. JAMA 1990;264:2639-43. [6.] Wish ED. Pre-employment drug screening [Editorial]. JAMA 1990;264:2676-7 [7.] Marwick C, Gunby P. Like other segments of culture, military has had to come to grips with drug abuse problems [News]. JAMA 1989;261:2784-5, 2788. [8.] Swotinsky RB, Chase KH. The Medical Review Officer. J Occup Med 1990;32:1003-8. [9.] Council on Scientific Affairs. Scientific issues in drug testing. JAMA 1987;257:3110-4. [10.] Clark HW. The role of physicians as medical review officers in workplace drug testing programs. In pursuit of the last nanogram. West J Med 1990;152:514-24. [11.] Executive Order 12564-Drug Free Federal Workplace. Fed Regist 1986;51:32889-93. [12.] DOT modifies testing procedures applicable to drug testing programs required in 6 transportation industries [Abstract]. Fed Regist 1989;54:49854. [13.] Americans with Disabilities Act of 1990. Implications for the medical field. West J Med 1991;154:599-4. [14.] Pransky G. Occupational medicine specialists in the United States: a survey. J Occup Med 1990; 32:985-8. [15.] Drug testing procedures handbook. Washington, D.C.: Department of Transportation, 1990. [16.] Aviation Medical Review Officers Guide (1990). Federal Aviation Administration, Office of Aviation Medicine, Drug Abatement Branch: Washington, D.C. [17.] Klonoff DC, Jurow AH. Acute water intoxication as a complication of urine drug testing in the workplace. JAMA 1991:265:84-5. [18.] Floren AE, Fitter W. Contamination of urine with diazepam and mefenamic acid from an Oriental remedy. J Occup Med 1991;33:1168-9. [19.] Hoyt DW, Finnigan RE, Nee T, Shults TF, Butler TJ. Drug testing in the workplace–are methods legally defensible? A survey of experts, arbitrators, and testing laboratories. JAMA 1987;258:504-9. [20.] Knight SJ, Freedman T, Puskas A, Martel PA, O’Donnel CM. Industrial employee drug screening: a blind study of laboratory performance using commercially prepared controls. J Occup Med 1990; 32:715-21. [21.] Medical review officer manual: a guide to evaluating urine drug analysis for implementation of the mandatory guidelines for Federal workplace drug testing programs. National Institute on Drug Abuse. Bethesda, Md.: Department of Health arid Human Services, 1988; DHHS publication no. (ADM) 88-1526.

ANDREW E. FLOREN, M.D., M.P.H. is medical director of McLeod Occupational Health Services, Florence, S.C. A graduate of the University of Texas Medical Branch at Galveston, Dr. Floren completed a residency in family practice at Florida Hospital, Orlando, and a residency in occupational medicine at the University of Oklahoma College of Medicine, Oklahoma City. He received his master’s degree in public health with an emphasis in health promotion from Loma Linda University School of Public Health, Loma Linda, Calif. Dr. Floren is certified as a medical review officer by the Medical Review Officer Certification Council.

COPYRIGHT 1994 American Academy of Family Physicians

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