How Accurate Is Hair Follicle Testing?
Hair follicle testing is said to be extremely accurate for detecting lower levels of drug use as well as drug use over a longer period of time. For example, there are some drugs that may be difficult to detect in a person’s urine once several days have passed. Hair follicle drug testing, however, may detect drug use that occurred weeks, or even months, before the person was tested. Drug test detection times may depend on the type of drug that was used, the frequency with which it was used, and the metabolism of the person who is being tested. Usually, however, hair follicle testing is accurate for much longer than a drug or urine test.
