If I have a patient that gets admitted on 10/22/15 but then utilization review advised this patient should be OBS and orders placed on 10/23, and I do have a code 44 done on 10/23, do I bill the first day as an inpatient since that is my initial orders, or do I start with 10/23 as OBS and bill 10/22 as initial OR do I bill the whole stay as OBS (I didn't think OBS orders could be retro'd) please advise as I am billing for Part B Medicare. thank you.