CPT code 86304 represents a quantitative laboratory assay for the cancer antigen CA 125, a tumor marker used in evaluating pancreatic cancer and other malignancies. As a laboratory diagnostic test, this code is important nationally for monitoring disease activity, guiding clinical decision-making, and informing treatment planning when CA 125 is clinically indicated. The test is typically performed in clinical or hospital laboratories on serum or body fluid samples and is billed under CPT coding standards.

Key payers discussed include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of the code's clinical context, typical site of service, and service type. The publication also covers payer coverage patterns and benchmark considerations where available, recent policy or coding clarifications affecting lab services, and practical billing considerations such as common modifiers and service line impacts. Where specific input data is missing, the text notes that information is not available in the input. This national-level summary is designed to inform clinicians, billing staff, and policy analysts about the role of 86304 in diagnostic workflows and reimbursement frameworks.