Summary & Overview
CPT 85366: Paracoagulation Test for Fibrin Degradation Products
CPT code 85366 denotes a laboratory paracoagulation assay performed on patient plasma to detect fibrin degradation products (FDPs). This diagnostic test is used to evaluate fibrinolysis and to aid clinical decision-making in conditions where abnormal coagulation or fibrin breakdown is suspected. Nationally, the code is relevant to hospital and clinical laboratories, hematology services, and acute care settings where rapid assessment of coagulation status can affect care pathways.
Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of the clinical purpose of the test, typical sites of service, and payer coverage considerations. The publication summarizes benchmarking context, common billing considerations, and relevant policy updates that affect laboratory reimbursement and coding practice for this test.
The report provides a practical reference for coding and billing staff, laboratory managers, and policy analysts seeking clarity on when 85366 is used, how it fits into laboratory service lines, and what national payers commonly consider when adjudicating claims for this paracoagulation assay. Data not available in the input will be noted where applicable.
Billing Code Overview
CPT code 85366 describes a laboratory paracoagulation test performed on patient plasma to detect the presence or absence of fibrin degradation products (FDPs). The analysis is a laboratory diagnostic service that assesses fibrinolysis and coagulation status by identifying fibrin breakdown products in plasma.
Service type: Laboratory diagnostic test
Typical site of service: Clinical laboratory or hospital laboratory
Clinical & Coding Specifications
Clinical Context
A typical patient is an adult who presents to an outpatient laboratory or hospital inpatient ward with signs or risk factors for abnormal coagulation or suspected disseminated intravascular coagulation (DIC), thrombotic or hemorrhagic complications, severe infection, or recent major trauma. A clinician orders coagulation studies and fibrin degradation product testing to evaluate for active fibrinolysis or clot breakdown. A phlebotomist collects a blood sample into a citrate tube; the laboratory performs plasma separation and the lab analyst runs a paracoagulation assay to detect presence or absence of fibrin degradation products (FDP).
The clinical workflow: the clinician documents indication in the chart, places the laboratory order, and labels the specimen. Specimen is received in the clinical laboratory, processed (centrifuged to obtain platelet-poor plasma), and the analyst performs CPT 85366 testing per laboratory protocol. Results are reported to the ordering clinician and interpreted in the context of concurrent tests (e.g., D-dimer, fibrinogen, PT/INR, aPTT, platelet count). Turnaround time varies by site of service—stat testing in emergency or inpatient settings vs routine in outpatient labs.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
00 | Default/No modifier specified |