Answer: You-ll need more than one CPT code for this encounter. Report 94640 (Pressurized or nonpressurized inhalation treatment for acute airway obstruction or for sputum induction for diagnostic purposes [e.g., with an aerosol generator, nebulizer, metered dose inhaler or intermittent positive pressure breathing (IPPB) device]) to cover the comprehensive service the allergist provided.
Because the physician also performed an office visit, you should also report 99213, based on your documentation of an expanded problem-focused exam with low-complexity decision-making.
Report 94640 instead of 94664 (Demonstration and/or evaluation of patient utilization of an aerosol generator, nebulizer, metered dose inhaler or IPPB device) since the allergist's primary intent was to treat the obstruction.
Caution: If you bill 94664 along with 94640 on the same day to Medicare, make sure you justify that the physician provided the 94664 service distinctly separate from the treatment. In this case, append modifier 59 (Distinct procedural service) to 94664 to notify the payer that the allergist performed 94664 separate from 94640. The documentation should include details on the medical necessity for separately providing this service.
Example: The allergist determined that the patient's plan of care should include inhalation therapy, or the patient is new to this therapy and does not know the administration techniques involved in the procedure.
The note should clearly identify that the physician demonstrated the inhaler to the patient separate from the administration for treatment. Otherwise, the insurer may think you are trying to report one service twice.
Tip: Though technically not required, it may help to link separate diagnosis codes to the E/M and the nebulizer treatment. For instance, you could link 786.05 (Shortness of breath) to 99213, and link the emphysema code (492.8) to 94640.