Answer: If an otolaryngologist sees a patient in the hospital after treating him in the office on the same day, you should assign only one E/M code: the hospital admit code (99221-CPT 99223 , Initial hospital care, per day, for the evaluation and management of a patient ...). When selecting the level of initial hospital care, also include the history, examination and medical decision-making involved in the same-day office visit E/M service. Be sure the inpatient record includes any office visit documentation the otolaryngologist may reference in his admission note.
CPT considers office visit and hospital care -per day- codes, meaning you should use only one of these codes for a given date of service. Based on this guideline, most insurers will deny a same-day office visit when billed in addition to a hospital care code. Don't assume that 99221-99223 are admission codes that have to coordinate with hospital admission dates. These codes are for initial hospital care, which you should bill when the initial face-to-face occurs.
As you indicated, if the otolaryngologist did not perform a face-to-face inpatient service on the same day as the office visit, you would separately bill each E/M service. Here's how:
Day 1: When the otolaryngologist admitted the patient to the hospital from the office but did not see the patient in the hospital, assign the appropriate-level office visit service (99201-99215, Office or other outpatient visit).
Day 2: If the patient is admitted to the ENT's service, and the first face-to-face inpatient-otolaryngologist encounter occurs within the first 24 hours of admission, report initial hospital care (99221-99223).