Question: Our family physician gave a patient with cluster headaches 20 minutes of oxygen therapy. How should we code for this? Is it included in the office visit? Kansas Subscriber Answer: There is no specific CPT code for administration of oxygen in the office. Use the appropriate E/M service code for the office visit (e.g., 99213) along with a prolonged services code(s) (99354-99357), if applicable, to capture the extra time involved. For example, if the oxygen therapy and other services rendered to the patient extended the visit to 45 minutes, which is 30 minutes longer than the typical time for 99213 (Office or other outpatient visit for the evaluation and management of an established patient ...), code 99213 plus +99354 (Prolonged physician service in the office or other outpatient setting requiring direct [face-to-face] patient contact beyond the usual service ...). For you to use the prolonged service code, the encounter must involve direct (face-to-face) physician contact with the patient.