Admission dates

If a patient is admitted to observation status through the Emergency Room at 10:00 pm on Sunday (phone call to admitting doctor Sunday night to approve the admission), but the admitting doctor doesn't actually arrive at the hospital until Monday at 9:00am to do the paperwork and to see the patient, do I bill the insurance for admit on Sunday or Monday? I'm billing for the admitting doctor.

BTW- The patient underwent an EGD later in the day on Monday and then was discharged Monday evening. I know something is not going to be paid here.

Thanks!

initial visit/discharge same day

Monday the day the physician first saw the patient is billed by attending in OBS. If Medicare and discharged same day, see 99234-99236( -25). Also, may need to query payer.