Pulmonology Coding Alert

Answer: You should report 94150 (Vital capacity, total [separate procedure]) for both vital capacity and peak flow. Both measurements are part of spirometry, which is the single most important test of pulmonary function.

During spirometry, the patient inhales and exhales with full effort, and measurements are taken of changes in volume of the respiratory system and airflow rates. The basic measurement of spirometry is the vital capacity, which measures lung volume. Vital capacity is the volume of air that is measured during a slow maximal expiration after a maximal inspiration. Normal range can vary with age, sex and height. Clinical information obtained from an analysis of the expiratory maneuver is most beneficial to the pulmonologist when making a diagnosis and treatment recommendations. To measure expiratory vital capacity, the patient inhales to his or her greatest lung volume and then exhales until air can no longer be expelled. The vital capacity is usually recorded in liters or milliliters.

The spirometer is also used to measure peak expiratory flow rate (peak flow), a measurement of lung mechanics. The peak flow is the highest expiratory flow rate (upper limit of air flow) from the lungs during expiration and occurs early in the expiratory phase.

Vital capacity, as a separate procedure, is more often used for monitoring, as is peak flow. Although there is a CPT code for vital capacity, there is no such code for peak flow. CMS does not intend to pay separately for monitoring procedures performed repeatedly on the same day.