I'm scheduled to take a "drug screen" sometime in the next week. Since it's with a fairly prominent company I fear it will be a hair drug test. The last time I smoked was New Years (3 hits). Prior to that I was a pretty infrequent user starting in September/october 2014. When I say infrequent I mean no more than 3 times a month and many times I would go 2-4 weeks without smoking. I am a white male and my hair is probably 3-4 inches long in back. The hair test uses "Elisa" and "GC/MS" if that helps. I know I would pass a urine test. Would I pass the hair test?

Also does anyone know what happened to dr.bill or how to get in contact with him? He seemed very knowledgeable about hair testing but I hadn't seen him post since 2012.

I'm going to guess that you will pass, but there are too many variables - always.
Plus, there are plenty of sites already that are pretty complete information. No sense reinventing the wheel and having to ask you more questions.
Dr. Bill has left this site and left no contact information.

If you have been doing it on a fairly consistent basis (3 times a month), you have a good chance of failing.

Are there any tips for passing? Seems like the detox shampoos are crap. Thanks for the quick responses, guys.

Nope, the shampoos and cleasers are just junk or scams, there is no way to pass except not use.

If it has been very little usage, and not often, you should pass. If the prior use was more regular, every week and often, then you would not.