The labs say that getting high 3 times over 90 days will cause a positive hair test result. You haven't smoked in 4 months and like I said they can only go back 3 months because it becomes inaccurate after 3 months because the chemicals in the hair begin to degrade. About the test being least sensitive for THC, I don't think that is right. This is from Quest and it is the levels they use for positive confirmation. If you notice, THC has the lowest threshold by far.

http://questdiagnostics.com/employer...esting_es.html
FakeBoobsRule Reviewed by FakeBoobsRule on . Hair drug testing Hi everyone, I am a new member. I have a hair drug test in about a week. I haven't smoked any marijuana in over 4 months. I looked through the discussion boards and I have only found a few threads of people actually answering back if they passed or not after taking the hair test. Before I completely quit 4 months ago, I was a relatively light smoker (maybe once or twice a month). I will be sure and let everyone know how my test turns out, to help others whose situation is similar to mine. Rating: 5