Growth of Drug Testing

By the mid-1970s, the field of drug testing had begun to take root, as many young Americans, both military and civilian, experimented with illegal drugs such as marijuana (tetrahydrocannabinol, or THC), lysergic acid diethyl-amide (LSD), and cocaine. Most urine testing for illicit drugs was being done either by forensic laboratories or in methadone treatment programs. In these programs, patients undergoing methadone substitution therapy for heroin addiction were monitored for illicit drug use and compliance with the methadone therapy (4). A modest amount of drug testing was being conducted in the workplace by innovative companies that recognized the productivity value of promoting a drug-free work environment.

Then on May 26, 1981, an event occurred that had tremendous repercussions on the drug-testing industry (5). There was a serious and deadly crash involving fighter aircraft on the carrier USS Nimitz, in the Atlantic Fleet. Fourteen servicemen died, 48 were injured, and $150 million in damage was sustained. Results from the crash investigation revealed that some of the crewmen involved had drugs in their system at the time of the accident. As a result of this incident, the Navy adopted a zero-tolerance drug policy that would ensure that it would be the first drug-free branch of the armed forces. The Navy was committed to ensure that a similar disaster would not occur again. All new recruits were subjected to screening; enlisted personnel and officers were subjected to "for cause" testing. The Navy urine-testing program became the model used by other branches of the US military and was later adopted by the armies and navies of several other NATO members.

Throughout the 1980s, urine drug testing continued to grow in the civilian world as well, with many Fortune 500 companies adopting the policies of, and the procedures for, a drug-free workplace. Some unions adopted these policies as well and undertook testing programs for their members. Drug testing, however, was not applied to government employees until another major deadly event occurred. At noon on January 4, 1987, Amtrak's Colonial passenger train headed out of Washington's Union Station. An hour later, disaster struck in Chase, Maryland, when the Amtrak Colonial collided with a locomotive operated by Conrail engineer Ricky Gates (6). An investigation by the National Transportation Safety Board revealed that Gates and his brakeman had THC in their urine and plasma, ignored the warning signals, and drove the locomotive into the path of the oncoming Amtrak train. This incident alone raised the awareness in both the private and public sectors of the importance of a drug-free workplace in industries like transportation that could endanger the public safety. As a result of both public and private pressures and by an executive order in September 1988, the National Institute on Drug Abuse (NIDA), a department within the US Department of Health and Human Services (HHS), published the first "Mandatory Guidelines for Federal Workplace Drug Testing Programs." The Department of Transportation was the first government agency to adopt the guidelines.

4. Regulation of Drug Testing 4.1. Federal Regulations

Before the NIDA published its mandatory guidelines in 1988, the only government regulation for drug testing was that the equipment and reagents used had to meet the Food and Drug Administration's (FDA) standards of an in vitro diagnostic medical device. Commercial suppliers of drug-testing products were required to submit test results that demonstrated to the FDA that the performance of the medical device was consistent with the product performance claims. If the results were satisfactory, the FDA would grant approval, known as a 510(k), which allowed the commercial sale of the product. Standards for sample collection, screening levels, and confirmation were, in many cases, left up to the discretion of the laboratory and/or the manufacturer. Each manufacturer of immunoassays had its own cutoffs for drug or metabolite assays and its own interpretations for measuring cross-reactivity to metabolites or interfering substances. In many cases, their claims and interpretations were written in ways to present their tests as comparable with competitive drug-testing products. With the issuance of the mandatory guidelines, everything changed. Drug testing in both the public and private sectors now had a standard to follow. NIDA, which later became The Substance Abuse and Mental Health Services Administration (SAMHSA), developed and implemented substance-abuse programs for the workplace that continue today. The first draft of the mandatory guidelines addressed the following important topics:

• Dilution and adulteration;

• Specimen collection and handling procedures;

• Training and qualifications of personnel;

• Screening levels;

• Confirmation testing and certifying test results;

• Laboratory certification.

Since 1988, the mandatory guidelines have been revised several times to incorporate technological advancements and process revisions. They became the de facto standard for all workplace drug-testing programs, including private industry. The regulations were revised and re-issued on August 1, 2001. That version of the mandatory guidelines incorporates many of the technological advancements that have been made in testing for illicit drugs. They address drug screening of urine as well as alternate matrix samples, such as oral fluid, sweat, and hair. They also address regulations and procedures for on-site testing, called point-of-collection testing (POCT). These standards were developed by SAMHSA's Drug Testing Advisory Board (DTAB). To develop standards for the products that represent the next generation in drug testing, this forum utilized input from industry representatives, laboratory professionals, and academics. A complete summary of the mandatory guidelines can be found on SAMHSA's web site: http://workplace.samhsa.gov/resourcecenter.

Meanwhile, the FDA has continued to review and issue 510(k) approvals for new assays, applications for tests of new equipment, and tests utilizing alternative matrices. In addition, the FDA has also begun to address standards for validation of on-site test devices. They have issued guidelines for validation and evaluation of POCT devices. These guidelines have not yet been issued, but are being followed for some new POCT devices. More information can be found at www.FDA.gov.

4.2. State Regulations

Of the 50 states, 31 have also adopted some type of employment drug-testing statute or regulation. These laws address which industries are required to test, what kinds of samples are allowed, and where the actual testing is done—e.g., laboratory or on-site. There are 14 states with voluntary laws that will qualify an employer for a discount on its workers' compensation premiums and/or a legal shield against litigation of drug testing that is conducted in accordance with the law. Additional states currently have laws under consideration that address workplace drug testing.

4.3. Determination of Cutoff Concentrations and Confirmations

Prior to the mandatory guidelines, the cutoffs for screening tests were established by each manufacturer supplying the immunoassay kit, and the confirmation level was determined by the sensitivity of the equipment and methodology used by the reference lab to confirm the nonnegative or positive sample. To publish the mandatory guidelines with established cutoffs for the initial or screening test and to set confirmation levels that ensure that true negatives will be identified and discarded and true positives will be identified and confirmed as positive was a formidable challenge for SAMHSA. Today, this problem becomes even more challenging, because levels were needed for oral fluid, hair, and sweat, as well as urine.

Although no system is perfect and absolute, the objective is to set the initial screening threshold at a level that will identify 95-98% of the true negatives as negative, but to also place it at a level that will pick up 100% of the true positives. Setting the appropriate cutoff level is further complicated when the immunoassay detects a primary metabolite with greater sensitivity than the parent drug. Finally, consideration is given to the differences in sensitivity found in commercially available technologies. The validation of the screening cutoff is usually done through several iterations of blind proficiency samples. Setting the confirmation cutoff is somewhat easier because it involves a chemical separation and measurement of the targeted drug or metabolite. It still means identifying the lower threshold or sensitivity level of the confirmatory method that will ensure that greater than 95% of all screened nonnegatives will be confirmed as positive. The cutoff values for screening and confirmation, in some cases, have to be set for the parent drug, as well as the drug's metabolite. Understanding the pharmacology of each drug's metabolism is key to setting the optimum screening and confirmation cutoffs. The cutoff concentrations for the initial and confirmation test can be found in Section 3.3 of the mandatory guidelines.

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