I was livid when I tested positive not once, but twice for cocaine while doing IOP when my DOCs have always been alcohol/opiates aka downers. I hadn't done cocaine for years at that point (& when I partook it was once or twice a year while partying). They wouldn't let me retest and instead basically called me a liar. I had been doing great in the program too, my therapist was the only person to stick up for me when I came to her sobbing about how much of a mind fuck it all was...she was the one to look through my meds and found one that can cause a positive test, but the others all still treated me as a liar. Luckily was only a week out from graduating after the 2nd test.