I have never trusted those test,and the main reason is because of human error.When you piss into the cup and leave the room thats the last time you see it.You have no idea where it goes or if it gets mixed up with anothers urine.You dont know who actually does the test,as far as Im concerned....they might not be able to pass the test themselves,cause Im sure they are not tested.Or it could be asprin,that has failed many.I had a situation years ago when the pee man arrived I was called into the room to be tested.....well the company always said that a computer spit the names out and thats how they choose who to test.So back to the pee man....when I walked into the room I asked the guy who was I susposed to be......he named another lineman.I told him that that name wasnt mine and that he needed to find the right person that fit the name....end of story.......but you know how some places are....they might suggest that since your here lets test you anyway.......no way.....the rules are the rules.