I want to know if anyone else has had any experiences like this. I took a urine test for work after not smoking for 3 weeks and I also took a detox drink and tested myself 4 times, 2 times before the test and 2 times immediately after. All tests were negative, they were the dip tests from a head shop. So a few days after I took the test I received a call from the lab saying they showed positive for THC. They did a carboxy-thc gc/ms confirmation with a cutoff of 15ng/ml and mine was at 33ng/ml, but the initial cutoff at the lab was 50ng/ml. So my question is if my confirmation test was 33 and the initial cutoff was 50 why did they have to do a confirmation, shouldn't I have passed the initial cutoff and a confirmation test was not needed? I hope this makes sense and hopefully someone can shed some light on this. I feel I'm getting screwed over.