A standard hair follicle screen covers a period of approximately 90 days. However, that depends on the growth rate of the hair. To do the screening, the hair will be cut as close to the scalp as you can get, and the most recent 1.5 inches are tested.
2 years ago
Last edited at 5:30PM on 2/12/2011
A hair follicle drug test doesn't play around. This test can determine drugs, going as far back to 90 days. If a person is trying to hide and say they don't take drugs, the employer will discover it, if they administer this test.