Fun story time: I once got informed of a drug test for a job I'd just accepted after a weekend of hard partying. I was on prescription opiods, Adderall, and ketamine. They called Monday morning at 9 to tell me I had to piss within 4 hours. I hadn't even slept yet. I should have lit that test up like a Christmas tree for everything except thc. It came back clean. They never asked about my prescriptions. I have 2 theories. 1) they don't actually test. 2) if too many things light up, they assume it's a calibration issue.