My boyfriend has been prescribed percocet for the past few months. He signed and agreement saying there would be routine drug tests. What are the doctors checking for? Do they just check the urine? They also gave him a blood test, is that part of this testing? If so why would they check both urine and blood. He thinks they were taking his blood for routine blood work, however, I think they were scamming him and checking his blood for drugs too. Maybe urine only shows up recent use of drugs> Any answers would be helpful