CPT code 94621 represents complex cardiopulmonary exercise testing (CPET) used to evaluate integrated cardiac and pulmonary function by measuring parameters such as minute ventilation and estimating ventilation-perfusion relationships. This diagnostic test is important nationally for assessing unexplained dyspnea, exercise intolerance, and for preoperative cardiopulmonary evaluation. Payers and health systems use the code to capture specialized physiologic testing that informs clinical decision-making for cardiology, pulmonology, and rehabilitation services.

Key payers covered in this overview include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a national perspective on clinical context, typical sites of service, and the aspects of documentation and service definition that drive coverage and billing. The publication also outlines benchmarking parameters where available, summarizes recent policy and coding guidance relevant to CPET, and clarifies how CPT code 94621 fits with related pulmonary function and exercise testing services.

This resource is aimed at clinicians, coding professionals, and policy analysts seeking concise guidance on the clinical intent and billing footprint of CPT code 94621, as well as the broader implications for utilization and documentation in hospital outpatient and specialized testing settings.