Excuseable reasons for failing drug test?

EZ, I agree that we must agree to disagree, lol... I respect your position immensely ~ as you know, your opinion means a lot to me whenever we're talking on a thread about drug addiction. Personally speaking, I get really sick of addicts who try to fool the tests ~ I have a couple family members who take great pride in doing just that.I was just merely speaking as someone who was educated and trained in chemistry. Also, I discussed this issue not so long ago with a dear friend who heads up the New Mexico State Forensics Laboratory, where they do umpteen drug tests per day. The problem with false positives is NOT present in the more expensive screens and tests, such as the GC-MS...it's in the cheaper tests that are usually used as a "first" screen.