I took a drug test yesterday and it came up positive for opitates...I have a legal prescription. It is now going to the lab to be checked...what are they checking for? Are they really analyzing it to see exactly what drug is in my urine? What if there are two diff. drugs? I took a hydrocodone and percocet the night before. Is that what they are looking for? I was told by my doctor that he can't write a letter saying that he prescribed them for me until the lab sends them something saying what drugs were in my urine. Is the lab looking for specifics or are they just going to call asking if I was prescribed opiates in general?