CPT code 85384 represents the technical component of a laboratory test that measures the clotting activity of fibrinogen. The code captures the hands-on, equipment-based processing and assay work performed by laboratory personnel to determine fibrinogen’s functional activity — an important part of coagulation assessment for bleeding, thrombotic risk, and perioperative evaluation. Nationally, this code matters because fibrinogen activity testing informs critical clinical decisions in emergency medicine, hematology, surgery, and transfusion management.

Key payers addressed in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise explanation of the clinical role of the test, common sites of service where the technical component is performed, and an outline of typical billing considerations. The publication provides benchmarks where available, summarizes relevant policy trends affecting laboratory service billing, and situates CPT code 85384 within clinical workflows for coagulation testing.

This national overview is intended for billing managers, laboratory directors, and policy analysts seeking a clear, practical reference on coding, site-of-service expectations, and the clinical context for fibrinogen activity testing.