Hair drug tests

So yeah, something was bugging me. I've heard hair drug tests are very rare, due to their cost and the amount of time it takes, as opposed to a urine test which takes about five minutes and are very cheap. However, rare doesn't mean nonexistant, and there's one thing I've been curious about.

Under what conditions would one expect to run into a hair drug test? I've never been able to get a straight answer, and I figured I'd ask tropers who've likely been out in the world, with many job which presumably require drug testing.

I tried asking IJBM, but they directed me here.

Long term tests most likely. If it were me, it'd be if I were doing a medical study and I wanted to be sure about the back ground.

I see so, so employers are unlikely to use such a thing?

Dunno. Not an employer, just saying how I would use them.

^^ Depends on the industry and specific organization. Some will do hair tests. (I think Raytheon and other defense contractors do) Some will just run the cheap piss tests if they test at all.

The benefit a hair test gives over a blood test or piss test is that it can reveal usage farther back in time, since the traces are deposited in the hair as the substance is used. So a hair test may reveal drug use six months ago, while a blood test will only go back a couple of weeks to a month, and a piss test may go back a week or so.