Answer: You should count the rehab ward services, including the transfer day, as hospital care. The rehabilitation ward is just another part of the hospital and not a separate facility, such as a nursing facility (99301-99316, Nursing facility services). Therefore, you should report subsequent hospital care (99231-99233, Subsequent hospital care, per day, for the evaluation and management of a patient ...) for all service days except the hospital admission and discharge days. The claims could include:
Day 1: Admission - 99221-99223 (Initial hospital care, per day, for the evaluation and management of a patient ...)
Days 2-3: Hospital inpatient - 99231-99233
Day 4: Transfer to inpatient rehabilitation ward - 99231-99233
Days 5-17: Rehab ward inpatient - 99231-99233
Day 18: Hospital discharge - 99238-99239 (Hospital discharge day management ...).