Summary & Overview
HCPCS G9143: Warfarin Genetic Responsiveness Testing
HCPCS Level II code G9143 denotes genetic testing for warfarin responsiveness, a pharmacogenomic assay used to identify patient-specific genetic variants that influence warfarin metabolism and dosing. This code captures laboratory-based genetic analysis using any technique and any number of specimens. Nationally, pharmacogenomic testing for anticoagulant management has implications for patient safety, individualized dosing, and potential reductions in adverse events related to bleeding or thrombosis.
Key payers in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of what G9143 covers clinically and operationally, typical sites of service, and the payer landscape addressed. The publication outlines benchmarks and coverage patterns, clinical context for pharmacogenomic testing of warfarin, and recent policy updates affecting coverage and coding practices. It also highlights practical billing considerations and commonly used modifiers (listed separately) that affect claim submission. This summary equips billing managers, laboratory directors, and policy analysts with the essential facts about G9143 and what to expect when managing claims and coverage for warfarin genetic responsiveness testing.
Billing Code Overview
HCPCS Level II code G9143 represents warfarin responsiveness testing by genetic technique using any method on any number of specimen(s). This service involves genetic testing to assess how a patient metabolizes or responds to warfarin, a commonly prescribed oral anticoagulant.
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Service type: Genetic diagnostic testing (pharmacogenomic testing)
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Typical site of service: Clinical laboratory or outpatient laboratory setting; testing may be ordered by ambulatory clinics, specialty practices, or hospital outpatient services.
Clinical & Coding Specifications
Clinical Context
A 62-year-old patient with newly diagnosed non-valvular atrial fibrillation is being evaluated to determine the optimal starting dose of warfarin. The clinician orders warfarin responsiveness testing by genetic technique to assess variants in genes such as CYP2C9 and VKORC1 that affect warfarin metabolism and sensitivity. A peripheral blood sample (or buccal swab) is collected in the outpatient laboratory or clinic. The specimen is sent to a molecular diagnostics laboratory where genotyping is performed using validated methods. Results are returned in the electronic health record and reviewed by the prescribing clinician or anticoagulation clinic to inform initial dosing and monitoring frequency. Typical sites of service include outpatient clinic, physician office, anticoagulation management service, or reference molecular laboratory. The workflow includes sample collection, specimen transport, lab processing and reporting, and clinical interpretation documented in the patient's chart.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | Use when reporting only the professional interpretation component if separate from the technical component. |