We have a pt that was admitted to observation, the next day she became a full inpatient admit. I have used the 99218-99220 for day one and 9922x on the next admit day. Is there documentation guidelines for this senario? What if the oppposite happens. Pt comes in full admit and then the next day she becomes observation? Do we need documentation for the different stay types? They are 2 different places of service.