CPT code 82104 covers laboratory testing to identify the alpha–1–antitrypsin phenotype, a clinically important assay used to detect protein expression patterns that indicate alpha–1–antitrypsin deficiency. This condition is linked to increased risk for chronic obstructive pulmonary disease and liver disease, making accurate phenotype determination relevant for diagnosis, risk stratification, and management decisions at a population level. Nationally, availability and coverage of phenotype testing affect diagnostic pathways for patients with unexplained emphysema or liver dysfunction.

Key payers included in this analysis are Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will learn how 82104 is defined clinically, where the service is typically furnished, and which payers commonly cover this laboratory testing. The publication summarizes benchmarks and reimbursement context, clarifies clinical indications tied to phenotype detection, and highlights policy updates or payer guidance that influence access to testing. Practical takeaways include expected sites of service, the clinical role of phenotype testing in alpha–1–antitrypsin deficiency evaluation, and national coverage considerations. Data not available in the input are noted where applicable.