Can a hair drug test reveal the exact dates you have smoked on?

[LizzyBeth]

Like if the last time i smoked was a year ago will it show it was a year ago, or just that i have smoked sometime

 

[Free Thinker]

They would not be able to know the exact date. They might be able to make an estimate, but that's unlikely too. Also, if the last time you smoked was a year ago, I don't think it would show up even on a hair test. I think smoke stays in hair for a few months tops.

 

[daddyrx]

Hair follicle drug tests are qualitative not quantitative. They can just tell whether or not a drug is there. The hair sample that is used is a 1.5 inch length measured from the follicle end. That equates to about the last 90 days. They'll use about 15-20 hairs for the test.