How far back does a hair drug test go?

My friend needs to know if he should even apply to a job that requires a hair drug test. So how long back do they take? Websites explaining are very welcome.

How far back does a hair drug test go?

copied from http://en.wikipedia.org/wiki/Drug_test#H...

[edit] Hair drug testing

Hair testing is quite accurate and can go back normally 3 months (6 months or longer possible with specialty tests), showing any drugs of abuse used in the detection window. As hair grows out, any drugs used are encased in the hair shaft, so the longer the hair, the longer back in the individual's drug history the lab can detect. Accredited hair drug testing labs, however, only use hair within about 2.5閳? cm of the scalp, and discard the rest. With head hair each 0.5 inch (0.8 cm) corresponds to about 30 days. This limits the detection history to about 90 days, depending upon the rate of growth of the individual's hair. Some people attempt to circumvent this through shaving their heads. In the absence of the required amount of hair on the scalp, body hair can be used as an acceptable substitute. It is also possible to use body hair to do hair drug testing, but since body hair grows slower, the head hair window of detection measures will not apply to body hair.

Additionally, for pre-employment hair testing, the inability to obtain a sample may be grounds for not hiring the individual. Hair Testing labs are regulated by CLIA or SAMSHA (not FDA).

Good luck.

How far back does a hair drug test go?

they do hair because its the most reliable test out there (and you will lose a chunk of hair in the back of your head as well) and since hair grows at a snails pace it generally takes about three months to get it out of your system. And by the way if that company does hair tests they WILL do random testing at unannounced times.

How far back does a hair drug test go?

It measures since that hair has been growing

How far back does a hair drug test go?

6 months. Your hair grows half an inch a month. You do the math. Usually, companies don't go for the hair test, but there are rapid detox recipes on the internet that supposedly work (stating what kind of drug it works for, how long the detox needs to last to be effective, etc)

How far back does a hair drug test go?

Most go back up to 6 months depending on the length of the hair tested every .5 inch goes back about 30 days. This site explains it and how shampoo doesnt really help. http://www.streetdrugs.org/drugtest.htm its the bottom paragraph.