Hi, i bill for a hospital in NY that does inpatient substance abuse treatment ( detox and rehab), they also do medication maintenance once patient is discharged, and pain management for patients who have to use opiates to treat medical conditions. I have been searching for days on the correct way to bill these encounters. as in correct cpt codes, pos when admitted and during outpatient visits. For all inpatient we are using cpt codes 99221-9922 and 99231-99233 with pos 21 for all admitted detox and rehab patients. Then for the medication management we use 99201-99205 or 99211-99215 with pos 23? can anyone tell me where to find help at.