Summary & Overview
CPT 85307: Activated Protein C Resistance Assay
CPT code 85307 represents a laboratory coagulation assay that determines the resistance of a patient’s plasma to the anticoagulant effect of activated protein C. This test is clinically relevant for evaluating suspected inherited or acquired thrombophilia and assessing risk factors related to abnormal coagulation. Nationally, accurate coding and clinical interpretation of this assay affect laboratory billing, clinical decision-making, and downstream management of patients with thrombotic disorders.
Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find an overview of the clinical context for ordering the assay, common sites of service where the test is performed, and which payers are commonly involved in coverage determinations. The publication also outlines benchmark expectations for coding and billing, summarizes policy considerations that influence reimbursement, and highlights areas where clinical documentation supports appropriate use of the test.
The content is intended to inform billing professionals, laboratory directors, and clinicians about the purpose of CPT code 85307, typical care settings, and what to expect from payer engagement and policy around this coagulation assay. Data not available in the input is noted where applicable.
Billing Code Overview
CPT code 85307 describes a laboratory assay that measures the resistance of a patient’s plasma to the anticoagulant effect of activated protein C. The test evaluates how plasma responds to activated protein C and is used in the clinical assessment of coagulation disorders related to protein C resistance.
Service type: Laboratory diagnostic test (coagulation assay)
Typical site of service: Clinical laboratory or hospital laboratory setting
Clinical & Coding Specifications
Clinical Context
A typical adult patient presents to an outpatient hematology clinic with a history of unexplained venous thromboembolism at a young age or recurrent thrombosis despite anticoagulation. The clinician suspects an inherited or acquired thrombophilia, specifically resistance to activated protein C (APC resistance) often associated with factor V Leiden. The workflow: the ordering provider (hematologist or primary care clinician) places an order for the APC resistance assay (85307). A phlebotomy technician collects a citrate anticoagulated plasma specimen and sends it to the clinical laboratory. The lab analyst performs the APC resistance functional assay, interprets clotting time ratios or normalized values, and reports results to the ordering clinician. Results are used alongside genetic testing (for example, factor V gene mutation analysis) and other coagulation studies to guide diagnosis and downstream management decisions. Typical sites of service include outpatient laboratory facilities, hospital clinical laboratories, and hematology clinics with on-site phlebotomy and laboratory services.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | Use when billing only the professional (interpretation) portion by a physician or qualified provider separate from the technical lab work. |