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Comprehensive screening ensures drug test accuracy.

Comprehensive Screening Ensures Drug Test Accuracy

The impact of drug abuse on the workplace, and on a larger scale, on our society is difficult to comprehend. Drug usage and sales have pervaded into the middle- and upper-class neighborhoods, crack houses abound and drugs are sold openly on street corners in many major cities. In 1985, the National Institute on Drug Abuse (NIDA) estimated there were 20 million cannabis users, 5 million cocaine users, 3 million stimulant or sedative users and over 100 million alcohol users.

Since this survey, cocaine in the form of crack has had a traumatic impact. Cocaine related deaths in 1982 were less than 200, but in 1986 they had increased to over 600. A parallel increase exists in the number of emergency room visits related to cocaine. Even more significant, it is estimated that 25 percent of all cases of AIDS are related to intravenous drug abuse, and approximately 70 percent of perinatal cases of AIDS are linked to I.V. drug use. The cost to society, already in the billions of dollars, continues to escalate in lost profits to industry and increased medical costs for drug related maladies.

Statistics show that the workplace is affected in many ways. Employees with substance abuse problems are estimated to have an absentee rate from four to eight times greater than that of the unaffected population and are at two to three times the risk of being involved in an industrial accident. Increased sick leave, grievance procedures related to job loss or injury and decreased productivity add to losses estimated at over $100 billion annually.

To combat the problem of substance abuse within the workplace, employers are turning to substance abuse testing and employee assistance programs to curb the amount of drug use within their respective employee pools. Companies have many testing options, but primarily use pre-employment testing. Also being utilized are routine monitoring programs performed at an annual physical and random testing. Random testing is generally confined to situations in which an overriding consideration of either security or public trust is at stake.

The most common reasons cited for instituting a substance abuse policy are safety for the worker or fellow worker, health concerns, decreased productivity, security and public trust. Security is generally relegated to industries that serve the public and face the possibility of an accident with devastating affects on the population--like the nuclear power industry. Public trust is generally cited in industries affiliated with transportation (airlines, rail and bus lines) which rely on the general public's utilization for profits.

On the other end of the spectrum are employee concerns. An employee expects a policy to be fair, to provide accurate and reliable results, confidentiality at all times and due process when a positive result is reached. Upon finding a positive result, employees are also concerned that an employee assistant program be provided for rehabilitation, rather than just termination.

The analytical methods currently in use for the detection of abused substances are well researched and numerous articles have been written concerning each technique. An initial screen which tests for the presence of abused substances is performed on urine samples to separate the drug users from the non-drug users. This procedure is followed by a confirmatory test based on a methodology independent from that of the initial screen test. The most widely used methodologies for screening for abused substances include enzyme mediated immunotransmittance, radioimmunoassay and fluorescent polarization immunoassay. These methods are able to detect major classes of drugs, the parent drug or major metabolites of a drug. While they offer excellent sensitivity, these methods are capable of producing false positive results. Therefore, it is mandatory that all initial positive screen results be confirmed by an independent second methodology.

Confirmatory methods include thin layer chromatography, gas chromatography, high pressure liquid chromatography and gas chromatography coupled to a mass spectrometer (GC/MS). According to the federal register published April 11, 1988, GC/MS is the only accepted and authorized confirmation method for cocaine, marijuana, opiates, amphetamines and phencyclidine (PCP).

GC/MS produces a "fingerprint" of the particular drug being analyzed. Typically, the three major ions of the drug are detected, allowing differentiation of over 1 million other drugs. While GC/MS offers high accuracy sensitivity and specificity, it is slow, very labor intensive and requires a high level of skill. Additionally, the high initial investment is costly, the instrument requires very high maintenance and, at this point, it is suitable only for low volumes.

Urinalysis is able to detect hundreds of different drugs, but the drugs most commonly tested for include amphetamines, barbituates, cannabanoids, cocaine and PCP. Each of these drugs has a window of detection in the urine, based upon its chemical properties, rate of metabolism and elimination by the body. Variances in an individual's height, weight and metabolic rate can all affect the excretion rates of the various drugs. This is why qualitative results are given when dealing with urinalysis testing. A quantitative value offers no insight into the pattern of drug use of an individual. A one-time user or an habitual user may both produce identical quantitative values. Therefore, the only conclusion to be made is that a positive drug test indicates that use has occurred. However, no information can be given concerning addiction or impairment, with the possible exception of alcohol, where scientific studies have established urine and blood levels and a corresponding degree of impairment.

Many questions have arisen concerning the question of false positives in the area of drug testing. NIDA has established cutoff values which allow discrimination between drug use and casual exposure. The most asked question concerns passive inhalation from passive exposure to marijuana smoke. NIDA has suggested that a value of 100 ng/ml of urine be used as the cutoff for distinguishing a positive from a negative result. Numerous studies have been performed where subjects were placed in a confined environment surrounded by other individuals who consumed marijuana. In a study by Cone et. al. published in the Journal of Analytical Toxicology in 1987, the researchers came to the conclusion that, "It is extremely improbable that subjects would unknowingly tolerate this type of noxious smoke environment for the length of time necessary to absorb the threshold dose of THC necessary to exceed a 100 ng/ml 9-CO2H THC cutoff."

A second concern is that of false positive test results for opiates following the ingestion of poppy seeds. Poppy seeds actually contain enough morphine and codeine to give true positive urine test results by any screen method currently on the market. One can differentiate this form heroin use by the fact that heroin is metabolized to a metabolite, while this metabolite is absent following poppy seed ingestion. Also of concern is the issue of false positive test results for cocaine following the drinking of coca teas. Coca teas were found to actually contain enough cocaine to give true positive urine test results and have subsequently been removed from the market following a ban by the Drug Enforcement Administration.

The most critical abuse has been leveled at the testing of amphetamines, since many over-the-counter medications react with the screen methods and give false positive results. Confirmation by GC mass spec is able to identify all of the analogues as well as amphetamine and methamphetamine and is able to distinguish between a true and false positive.

With the growing interest in substance abuse testing, many laboratories have scrambled to include themselves in this new and lucrative market. The proliferation of labs has raised the question of standardization and reliability of laboratories. Employers are faced with the task of choosing a laboratory which will offer competent service. This task is generally placed on the medical or personnel department which typically has little knowledge in the area of substance abuse testing. The initial questions which should be answered when looking at a laboratory include certification, staff qualification, chain of custody procedures, methods used to insure confidentiality and whether technical assistance and expert testimony is provided by the laboratory. Employers should also question what quality assurance or quality control programs are being used by the lab and whether blind specimens are submitted to the laboratory without prior knowledge. Finally, a visit or inspection of the facilities is recommended by the company and attorneys representing the company to assure that a quality program is in operation.

NIDA, in conjunction with the Department of Human and Health Services, have established guidelines which labs must meet to be certified by these agencies in the area of drug testing. These guidelines were set as minimum standards for those laboratories seeking to be included in the testing of employees in the federal sector. These standards dictate requirements for facilities, security, personnel qualifications, acceptable analytical methods and guidelines for reviewing and reporting results. These guidelines are meant to be the "gold standard" to which all laboratories will be compared. Currently, there are approximately 13 laboratories in the country which have met these minimum requirements.

The final question to be answered is whether these substance abuse detection programs are having any effect in the workplace. Southern Pacific Railroad instituted a substance abuse program in 1984 and has seen a dramatic decline in the number of positive tests, injuries on an annual basis, accidents attributed to human error and the cost of the accidents. The U.S. Navy instituted a drug testing program in 1980 and has seen a subsequent decrease in the percent positive ratio and the loss and productivity due to drug use. On a local scale, Lincoln Plating, a small business located in Lincoln, NE, has seen their work-time loss accident rate decrease by over 45 percent over an 18 month period when compared to the 18 months prior to adopting a substance abuse program. In addition, their pre-employment testing has screened out approximately one out of every four applicants due to a positive substance abuse test result. The combination of an effective preemployment and for cause testing program has resulted in decreased insurance rates.

The major issues facing substance abuse testing may yet be decided in the courts. Only by using qualified laboratories will companies be assured that actions taken based on positive analytical results will be upheld in challenges towards the policy.

Albert L. Giles is vice president of administration and marketing for Independent Forensics in Voorhees, NJ. Gregory R. Post is a clinical chemist for Pathology Medical Services, P.C. in Lincoln, NE.
COPYRIGHT 1989 Risk Management Society Publishing, Inc.
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1989 Gale, Cengage Learning. All rights reserved.

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Author:Giles, Albert L.; Post, Gregory R.
Publication:Risk Management
Date:Sep 1, 1989
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