|Hair testing is the most accurate and effective method of finding users of drugs of abuse. Using a small sample of hair cut at the scalp, hair analysis evaluates the amount of drug metabolites embedded inside the hair shaft.
When compared to the more traditional forms of testing, i.e. urine testing, hair samples can detect a longer period of drug use. With urine, most drugs are undetectable if urinalysis is done more than 2-3 days after use, with the exception of marijuana, which may be detected for a slightly longer period of time. After the 2-3 day period, a urine donor will test negative and slip through the urine screening process. With hair samples, the only time limitation for detecting drug usage is imposed by the length of the donor’s hair. Each ? inch of head hair provides a 30-day history of drug use. The standard for the industry is to test 1.5 inches, which provides a 90-day history of the donor’s drug use.
If no head hair is available, body hair can be used. Bleaches, shampoos and external contaminants (i.e. marijuana smoke) have no known impact on test results.
The validity of hair testing has been upheld by courts across the United States in both civil and criminal cases. Clicking the link below will provide a non-exclusive list of cases upholding the use and admissibility of hair testing in a wide range of cases, including employment and custody matters.