Michigan Subscriber Answer: You should report observation services for each day the allergist treated the patient. If that time spans two days, you are correct to report two codes.
Caveat: Physicians have to back up these claims with notes proving the patient was admitted to observation and the number of days in observation. Make sure the documentation clearly demonstrates that your allergist provided face-to-face care on two days. Linking each observation code with its date of service (DOS) is the best way to prove the services. Here's how:
Monday encounter: For the first day of observation, report 99219 (Initial observation care, per day, for the E/M of a patient, which requires these three key components: a comprehensive history, a comprehensive examination, and medical decision-making of moderate complexity). On the claim, make sure you note the calendar date that the patient received 99219 services.
Tuesday service: For the day the physician released the patient from observation, report 99217 (Observation care discharge day management ...). Use the Tuesday DOS to indicate the calendar date that the patient received 99217 services.