When constructing a program that ensures a drug-free workplace, it is always important to understand facts versus myths. Below are some very common misconceptions that could be impacting your drug testing program (continued from part 1).
Myth: My lab result was negative but my instant/point of care test was positive. I need a new cup vendor.
Fact: They could BOTH be right! Instant/point of care test results depend on combined activity in a given drug class. The instant test is designed to simply indicate if further testing is needed, and is not a definitive test. It’s like asking someone to let you know when the temperature is 87.3 degrees. He can reach out the car window and tell you “Well, I think it’s close, but I can only confirm using the thermometer.” Similarly, when the instant urine or saliva result is “positive,” it is indicating that an illegal substance may be found. The sample is then sent to a lab for confirmation—the thermometer is analogous to the mass spectrometer. The gas and liquid chromatography massspectrometers are highly specialized instruments that are able to identify individual drug metabolites based on their molecular “fingerprints,” and check the accuracy of the instant test with a high level of specificity. The mass spectrometry analysis will tell you whether, for example, a substance is present as indicated by the instant test, but is not an illegal substance. Conversely, mass spectrometry can tell you that not only was an opiate found, but it was oxymorphone. The mass spectrometry result is the final result.
Myth: Hair testing is ‘new science’ and is not ready for primetime.
Fact: Hair testing was brought to the commercial marketplace in 1987 after ten years of extensive research and development. With millions of hair tests already conducted for employers, child protection agencies, and police forces all over the world, the scientific validity has been proven over the last twenty-five years in numerous federal, state, and military courts, as well as in private arbitrations. Hair testing is most commonly used to identify lifestyle drug users at the pre-employment stage – thereby preventing them from entering the workplace and bringing associated risks – and use of random hair testing is also growing. There are important things to look for when selecting a hair testing lab, including FDA clearance of screening tests and accreditation for hair testing by the College of American Pathologists (“CAP”), which requires compliance with rigorous forensic testing standards. Finally, the lab needs to effectively address external contamination through extensive and validated wash procedures, in order to distinguish between drug ingestion and exposure.
Myth: Confirmed levels of metabolite concentrations in urine are directly proportionate to usage (i.e. the more drug you take, the more you have in your system).
Fact: There are several studies discussing how drug metabolite disposition varies among individuals and dosage levels. In the previously referenced manuscript by Dr. Marilyn Huestis and Dr. Edward Cone, the purpose of the study was to “review the disposition of methamphetamine in oral fluid, plasma and urine.”2 In the study, they administered single and multiple doses of methamphetamine to 5 non-drug users. The multiple dose study included Subject BB receiving sequential doses of 20 mg methamphetamine (given at 0, 24, 48 and 72 hours), as well as Subject S receiving non-sequential doses of 10 mg methamphetamine (given at roughly 0, 48, 72 and 144 hours). Although Subject BB ingested twice as much drug during the study, Subject S demonstrated considerably higher levels of methamphetamine in urine. While this study focuses on the different detection times in oral fluid, plasma, and urine, it also shows that the disposition of drugs in bodily fluid is NOT necessarily directly proportionate to dosage or ingestion. Besides individual variations, concentrations of drugs in these liquid matrices are completely dependent on the time lapsed between ingestion and sampling, and therefore results can never be used to indicate the magnitude of the dose.
Highlighted above are just some of the common myths in the industry. It is always a good idea to reach out to your drug testing professionals to get the most up-to-date information and to ensure that your program is not being influenced by any of these or other common misconceptions.