Summary & Overview
CPT 85384: Fibrinogen Clotting Activity, Technical Component
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.
Billing Code Overview
CPT code 85384 describes a laboratory procedure in which a lab analyst performs the technical steps of a test measuring the clotting activity of fibrinogen. This service is a laboratory diagnostic test focused on assessing fibrinogen function, typically used in coagulation evaluation.
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Service type: Laboratory diagnostic (technical component)
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Typical site of service: Clinical laboratory or hospital laboratory where technical processing and analysis of blood specimens occur.
Data not available in the input for associated taxonomies, ICD-10 diagnoses, and related codes.
Clinical & Coding Specifications
Clinical Context
A 62-year-old hospitalized patient on warfarin with chronic liver disease develops spontaneous bleeding and prolonged prothrombin time. The treating team orders coagulation studies including a fibrinogen activity assay to evaluate clotting function. A blood specimen is collected in a sodium citrate tube and transported to the hospital core laboratory. In the lab, a medical laboratory scientist or certified clinical laboratory technician performs the technical steps of a fibrinogen clotting activity test (CPT 85384) using a Clauss or comparable clot-based method. The test run includes specimen preparation, reagent mixing, timed clot detection, and generation of a fibrinogen activity result reported to the ordering clinician. Results inform decisions about transfusion of cryoprecipitate or fibrinogen concentrate and adjustment of anticoagulant therapy. Typical sites of service are hospital inpatient laboratory, outpatient hospital laboratory, or an independent clinical laboratory performing routine coagulation testing.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | When billing only the physician/pathologist interpretation portion is allowed and reported separately |
TC |