Hair testing is a powerful tool for the detection of drug and alcohol abuse. Hair provides a long-term history of drug and alcohol abuse by trapping biomarkers in the keratin fibers of the growing hair strand. When collected close to the scalp, hair can provide up to a 3 month history of drug and alcohol abuse. Hair offers a specimen that is simple to collect, somewhat difficult to adulterate, and easy to ship.
 
A 1.5 inch specimen of about 200 strands of hair (about ¼ inch in diameter, the size of a #2 pencil) closest to the scalp will give 100 mg of hair. For EtG, add-ons and/or tests above 10-panel, 150 mg of specimen is required.