If a dr sees a patient (or two) in the hospital, usually they bill independently from the hospital. It's actually the same as if they saw the patient in the office, except they use the POS 22 for inpatient and put the hospital info in box 32 (including hospital's NPI). All other coding is the same with the exception of reading things like EKG's, etc, where the hospital performed the technical component so the dr is only billing for the professional component using a 26 modifier. The hospital will provide the dr with a demographics sheet on the patient that has all info needed for billing.
Michele