Does anyone know the correct codes and/or modifiers to bill Medicare Part B for IOP Treatment performed in a Facility setting? Also, can this be performed by a LISW? I know Medicare Part B services are to be billed on a CMS 1500. If you bill a 90853 the reimbursement is only $27.66 and they are seeing the clients 3x week for 3 hours a day so I know this is not the correct code for this service. Anyone with any knowledge on this your response would be very helpful. Thank you.