REVIEW OF ALTERNATIVE SPECIMENS FOR WORKPLACE DRUG TESTING:
Drug use in the workplace is a problem in the United States with a large number of illegal drug users potentially posing a danger to themselves and others. Since the 1970s, urine drug testing has been the most common technique for detecting drug use in the workplace. Although widely utilized, problems such as the lack of long-term drug detection, the inability to correlate urine drug test results with drug impairment and blood drug concentrations, opiate source differentiation, specimen adulteration by donors, and privacy issues continue to affect the industry. The testing of urine alone may not continue to guarantee a drug-free workplace.
The selection of a specimen for drug analysis is influenced by a variety of factors, principally ease of specimen collection, analytical and testing considerations, and interpretation of results. Recently, interest has shifted from urine towards other specimens that can provide distinct advantages. These specimens include oral fluid (saliva), hair, and sweat. Oral fluid was previously limited to aspects of therapeutic drug monitoring and insurance testing, but the introduction of several laboratory-based drug test systems and on-site devices has expanded drug testing capabilities. Hair testing was originally considered for metal detection and nutritional evaluation, but the development of specialized techniques for drug identification by immunoassay has increased its use. Sweat testing is a newer technology with the introduction of a commercial sweat patch technology.
Although these techniques are available today and can be used wherever legally allowed, widespread acceptance and use require a comprehensive understanding and development of each of the specimen’s relative merits. The test for acceptance was whether the specimen would be accepted in the federally regulated workplace program. Urine testing was first introduced in 1987 and has been the mainstay since that time.
In 1997, the Department of Health and Human Services (HHS) began evaluating alternative specimens for inclusion into its program to possibly complement and/or to substitute for urine. Urine was recognized as having many distinct advantages, but also suffers from some disadvantages. The use of other specimens may overcome some of the disadvantages of urine, but may themselves present issues of their own.
The Substance Abuse and Mental Health Services Administration’s Division of Workplace Programs (SAMHSA), through its Drug Testing Advisory Board, has evaluated these specimens and has provided the public with a set of proposed guidelines. These are considered mandatory for federal employees, but they are often utilized additionally in the private sector.
SAMHSA recently announced that it has accepted the recommendations of its technical advisory committee, the Drug Testing Advisory Board (DTAB), and will proceed with revisions to the Department of Health and Human Services (DHHS) Mandatory Guidelines for Federal Workplace Drug Testing Programs. The changes will include: (1) expanding the drug testing panel to include additional Schedule II prescription medications (e.g. hydrocodone, hydromorphone, oxycodone, and oxymorphone), prescription painkiller opioid drugs, and (2) including oral fluid as an alternative specimen for Federal workplace drug testing programs. The additions of testing for prescription medications and having oral fluid as a specimen for drugs of abuse testing are seen as measures to strengthen the existing federal drug abuse prevention and control programs.
The addition of oral fluid as a specimen for drug testing is important on two counts. First, it helps address the continuing concerns about adulteration, substitution, and tampering with urine specimens in workplace testing. Oral fluid specimens are more difficult to compromise. Second, oral fluid collections are essentially an “observed collection” without additional invasion of privacy concerns, and provide an alternative for individuals who cannot produce adequate, acceptable urine specimens for drug testing purposes.
The detection time of drugs and drug metabolites in oral fluid is relatively short, and the analyte (drug) concentrations in the fluid are generally proportional to those found in plasma. The detection times using any method is dependent on the pharmacologic properties of each drug being tested for as well as the amount of drug consumed by the person being tested, the frequency of consumption, the time between the drug consumption and the test, the individual’s metabolism and the sensitivity of the testing method. For most drugs, the window of detection is 18 to 36 hours. Various studies have shown that amphetamines/methamphetamines remain in the saliva in sufficient quantities for detection for up to 50 hours, whereas cocaine can be detected for up to 12-36 hours, opiates for up to 24 hours and marijuana for up to 24 hours.
Any on-site drug test (saliva or urine) can only deliver a general “screening” result. After any presumptive positive screening result, a confirmation analysis (e.g. GC/MS or GC/MS/MS) should be conducted. The confirmed positive result should then be verified by a licensed Medical Review Officer (MRO). This process is also required for any type of urine testing, including lab-based and Point of Care tests.
It is possible with some drugs to correlate the concentration of analyte in the oral fluid with behavioral effects. Recent research suggests that the detection window for oral fluid is longer than previously expected when analytical sensitivity is increased. A number of devices are available for collecting oral fluid. Both oral fluid and urine are amenable to testing at the point-of-collection, thus increasing their utility in roadside drug detection by law enforcement, parole/probation testing, and clinical assessments in occupational medicine clinics and hospital emergency room settings.
Two types of commercially available oral fluid testing systems exist. The first type involves the on-site collection of oral fluid which is shipped to a forensic laboratory for analysis. The second type involves the on-site collection and testing of oral fluid. Positive samples are subsequently shipped to a forensic laboratory for confirmatory testing.
A recent study conducted by Langel et al. looked at nine different oral fluid collection devices to evaluate their suitability for collecting samples for drug analysis. All of these devices/systems require the samples to be sent to outside forensic laboratories affiliated with the manufacturer of each device. These devices included the Greiner Bio-One, Orasure Intercept, Immunalysis Quantisal, StatSure Saliva-Sampler, Cozart, Sartedt Salivette, Malvern Medical OraCol, Acro Biotech Salicule and Varian OraTube. The study revealed substantial differences between the oral fluid collection devices on the market. The most significant problem involved the testing for marijuana with some devices proving inadequate for this analysis.
Several authors have studied the accuracy of on-site/rapid point of collection oral fluid drug testing devices. In general, these studies demonstrated variable performance with some devices performing well for the analysis of some drug classes but poorly for others.
The use of oral fluid testing may increase exposure to liability because, although on the rise, this method has not been judicially scrutinized. Many states have enacted statutes regulating both lab-based and point of care (on-site) use of oral fluid for employment drug testing. Such statutes define what constitutes an appropriate specimen for purposes of drug testing, often including oral fluid in this definition. Some states only allow lab-based oral fluid testing while other states permit point of care testing as well. Lastly, many of the statutes require the use of confirmatory testing and review by an MRO.
Because there is no judicial authority accepting this method, the use of a Medical Review Officer (MRO) is not any less important. For positive test results, non-saliva confirmation tests and an MRO is recommended.
Hair analysis enables long-term detection of drug use. Unlike conventional specimens in which drugs and drug metabolites have a limited dwell time, hair provides a retrospective, long term measure of drug that is directly related to the life span of the hair matrix. Differences in color and texture of hair may cause a variation in detection response. This, however, may not be substantially different than variations in drug detection in urine based on water content. Hair is a well-accepted method of testing for pre-employment and for random sampling. It is not applicable in an accident situation.
The physiological distribution of drugs in the human body suggests a varying relationship among drugs to be found in different specimens. Workplace federal programs focus on five classes of drugs of abuse, including marijuana/metabolites, cocaine/metabolites, opiates/metabolites, phencyclidine, and amphetamines. Private employers have greatly expanded the scope of testing and 10 panel drug screens and more are not uncommon. The analytes recommended for workplace testing are well established and specific cutoff concentrations have been published, but continue to evolve.
Urine and oral fluid can be used for all purposes, whereas hair is limited to pre-employment and random testing. Hair may be useful for return-to-duty/follow-up if it had been used previously and been demonstrated to be negative in the same individual. The quantity of each specimen collected needs to be sufficient for initial testing, confirmatory testing, and split specimen preparation.
References are available upon request.