Question: Which code set should we use when the gastroenterologist admits a patient to observation care on Friday night and discharges him on Saturday morning? These are separate dates, but the total time is less than 24 hours. Georgia Subscriber Answer: In this situation, you’ll refer to the code range 99218-99220 (Initial observation care, per day, for the evaluation and management of a patient …) for the first day of observation care. You’ll use these codes when the provider admits and discharges the patient on different calendar days, even if fewer than 24 hours passed between admit and discharge. This code set represents the first day of those observation services. When you’re using the 99218-99220 observation codes, you should be able to report 99217 (Observation care discharge day management …) for the next-day discharge. For instance: A patient presents to the ED with persistent vomiting and a severe headache, so the gastroenterologist sees the patient for a possible stomach obstruction, as she has been unable to hold down liquids for over 24 hours. The gastroenterologist determines the patient is suffering from dehydration; he administers a dose of Ondansetron, after which the patient is able to tolerate sips of liquid. The gastroenterologist admits the patient to observation status at 11 p.m. Friday to ensure that she can maintain oral intake; she is discharged at 4 a.m. Saturday. Notes indicate a detailed history, comprehensive examination, and a low level of medical decision making (MDM). The final diagnosis is dehydration with headache and persistent vomiting. For the first day of this encounter, you’ll report 99218 with E86.0 (Dehydration), R11.10 (Vomiting, unspecified), and R51 (Headache) appended to represent the patient’s condition. For the second day, report 99217. Remember that before reporting a discharge day code, there must be a face-to-face encounter. Therefore, the provider would have to see the patient on the first day (to report a code from the 99218 series, as noted above) as well as on the discharge date. These codes describe the observation services on a specific calendar day, so if you transcend midnight, a second observation code (in this case 99217) should be reported for the discharge day of observation. Keep in mind that you must document the face-to-face encounters for both dates of service.