Health and Fitness

A hair drug test is a specialized kind of drug test that attempts to determine the presence of certain classes of drugs in the hair samples of a subject. The hair sample used for conducting the test may be taken from the head or other body part, in some cases extracting the hair from beneath the skin. A hair drug test can trace the history of substance (drug) abuse in a subject to as far back as six months. A number of points of criticism have been raised against hair drug tests, questioning their validity and social implications for certain ethnic groups. However, the procedure is increasingly being used in the US for various purposes.