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A 19-year-old male asked:

they smoked weed about 3 weeks ago for the first time and about through up after one hit and they have a hair drug test next week will he pass?

2 doctor answers2 doctors weighed in
Dr. Ed Friedlander
Pathology 44 years experience
Good: It's unlikely that one use will show up three weeks later. If it does, it will be at a low level and you can say it's secondhand smoke. This is not the place to argue the wisdom of the cannabis laws or screening for its use. I simply hope that under the present conditions, you'll obey the law, and also not use a more dangerous intoxicant simply because it clears the body faster.
Dr. Ed Friedlander
Pathology 44 years experience
Provided original answer
On re-reading noticed it's a hair test. This is insensitive and I would be very surprised if it detected a single use. Second-hand smoke might still be a defense. Good luck.
Apr 12, 2013
Dr. Donald Alves
Emergency Medicine 24 years experience
If really ONE time..: ...Probably yes. Hair looks for longer term use over longer time. So may survive the test. Best to avoid drugs altogether.

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