Summary & Overview
CPT 85397: Functional Coagulation/Fibrinolysis Activity Assay
CPT code 85397 denotes a laboratory test that measures the functional activity of a specific biochemical compound involved in coagulation or fibrinolysis when no distinct, specific code exists. This catch‑all functional assay code matters nationally because it covers specialized, clinically important tests used to diagnose or monitor bleeding and clotting disorders that are not captured by standard procedure codes. Use of this code affects laboratory billing, payer adjudication, and clinical reporting for complex hemostasis evaluations.
Key payers considered in national coverage and payment discussions include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of the clinical intent of the code, typical sites of service, and the common payer landscape. The publication provides benchmarks for utilization and payment where available, summaries of relevant policy considerations that influence coverage and reimbursement, and clinical context describing when such functional assays are applied in practice. The report also outlines typical documentation and coding scenarios and highlights areas where policy clarification or additional coding specificity is often sought.
Data not available in the input for some fields is noted where applicable.
Billing Code Overview
CPT code 85397 describes a laboratory procedure in which a lab analyst measures the functional activity of a specific biochemical compound related to coagulation or fibrinolysis for which no separate, specific procedure code exists. This is a specialized laboratory service used to assess functional properties of clotting or fibrinolytic factors when standard, named assays are not applicable.
Service type: Specialized coagulation/fibrinolysis functional assay
Typical site of service: Clinical laboratory or hospital laboratory setting
Clinical & Coding Specifications
Clinical Context
A 54-year-old hospitalized patient with a recent unprovoked deep vein thrombosis and an abnormal routine coagulation screen is referred to the hospital laboratory to evaluate the functional activity of a specific coagulation-related protein for which there is no unique CPT code. The ordering clinician requests a specialized functional assay (for example, a custom or non-standard activity assay of a clotting factor inhibitor, a fibrinolysis regulator, or a rare protein cofactor) to clarify bleeding versus thrombotic risk. The clinical workflow begins with specimen collection (usually citrated plasma) from the inpatient or outpatient phlebotomy service, transport to the coagulation laboratory, accessioning and verification by the lab analyst, performance of the specialized functional assay using validated methods, and review of results by a pathologist or coagulation specialist. Results are reported into the electronic medical record with interpretive comments to guide anticoagulation management, perioperative planning, or further diagnostic testing. Typical site of service is a hospital clinical laboratory, specialty reference laboratory, or outpatient hospital-based lab performing coagulation testing.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | Use when billing only the professional interpretation component if the lab separates technical and professional billing. |