A pdoc is the same as your medical doctor. The pdoc is a medical doctor. The pee tests usually test for a number of things in addition to checking for substances. The doctor needs to make sure you are medically healthy for the medication. If they don't they aren't doing their jobs. Given that pcps and pdocs don't communicate, often pdocs have to order their own tests instead of going off of what you would have been tested for when you went in for your annual physical with your doctor.