Can hair testing detect one-time drug use? The simplest answer is most likely not. The Laboratory Supervisor at Quest Diagnostics, Jarod Rowland, explains the strengths and limits of hair tests in the following statement.
“One of the stand-out benefits of hair drug testing is its sensitivity and its long window of detection of up to 3 months of prior drug use. Because of this, hair testing is often referred to as a ‘lifestyle test.’ However, that long look-back window is not necessarily the best way to detect a single instance of drug use in scenarios like post-accident testing. Instead, hair testing is more informative of a repeated pattern of drug usage during the broader detection window. The detection of a single drug-use event is complicated by the extremely small percentage of the total dose incorporated into the growing hair during that single use event.”
Urine testing is better suited to provide results for employers who want to detect recent drug use. Employers have incorporated a combination of drug tests. Many use urine and hair as their preferred combination. Some perspective employees get themselves "clean" for a pre-employment drug screen, but the hair test discovers a long-tern pattern of drug use.
When employers begin to build a drug-free workplace program, they should consider that the different specimen types have unique benefits. Employers can conduct their own research to see what specimen type will be a better fit for their drug testing program.
SOURCE: Quest Diagnostics