A false positive results only when a confirmation test is not performed, and there is no medical review. A GC/MS is definitive and defensible., Some irresponsible employers and drug testing providers do not confirm non-negative screening tests and subject themselves to major legal liability.
At InOut Labs, ALL non-negative screening tests undergo confirmation testing and medical review. Every single one.
Urine drug test collection procedures are described by the Department of Health and Human Services in 49 CFR Part 40, and are generally the same for regulated testing and non-regulated. Most regulated testing is for employees regulated by the US Department of Transportation and often referred to as DOT drug testing.
The step-by-step urine specimen collection protocol includes verifying the donor’s identity, securing the collection area to reduce opportunities to cheat, and completing paperwork that establishes a chain of custody. There is zero opportunity for an individual’s specimen to be mixed up with someone else’s specimen.
Some prescribed medications will be detected in a urine drug test. For this reason it’s important the a Medical Review Officer (MRO) be involved. An MRO reviews all positive drug test results and will verify all prescriptions. If a positive result is due to a valid prescription, the result is reported as a negative. This protects both the employer and the donor. For more on the MRO, see here.