G9840 RAS Mutation Testing HCPCS Reimbursement | OpenPayer

Summary & Overview

HCPCS G9840: RAS (KRAS and NRAS) Mutation Testing Before Anti-EGFR Therapy

HCPCS Level II code G9840 denotes RAS (KRAS and NRAS) gene mutation testing performed prior to initiating anti-EGFR monoclonal antibody therapy. This molecular diagnostic code captures pre-therapy genomic assessment that guides targeted treatment decisions in oncology, particularly for tumors where EGFR-targeted agents are considered. Nationally, standardized coding for companion diagnostic testing supports consistent coverage determinations, quality measurement, and clinical decision support for precision oncology.

Key payers in the analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of clinical context for RAS testing, typical sites of service where the testing is performed, and the implications of having a discrete HCPCS Level II code for tracking utilization of pre-therapy molecular diagnostics. The publication summarizes benchmark considerations, payment and coverage themes across major payers, and policy updates relevant to billing and documentation. It also outlines how this code fits into care pathways for patients being evaluated for anti-EGFR monoclonal antibody therapy.

Intended readers will gain practical reference material for billing and administrative workflows, payer coverage landscape, and the clinical rationale for RAS mutation testing before anti-EGFR moAb initiation.

AetnaBlue Cross Blue ShieldCigna HealthUnitedHealthcareMedicareG9840HCPCS Level IIRAS mutation testingmolecular diagnosticsanti-EGFR therapyoncologygenetic testingprecision medicinelaboratory billing

Billing Code Overview

HCPCS Level II code G9840 represents RAS (KRAS and NRAS) gene mutation testing performed before initiation of anti-EGFR monoclonal antibody (moAb) therapy. This service is a molecular diagnostic test used to detect mutations in the KRAS and NRAS genes to inform the use of anti-EGFR targeted therapies.

Service type: Molecular diagnostic / genetic mutation testing
Typical site of service: Oncology clinics, hospital outpatient laboratories, and specialized molecular pathology laboratories

Clinical & Coding Specifications

Clinical Context

A 64-year-old patient with newly diagnosed metastatic colorectal adenocarcinoma is evaluated in an oncology clinic to determine eligibility for anti-EGFR monoclonal antibody therapy (cetuximab or panitumumab). Prior to initiating therapy, the treating oncologist orders molecular testing for RAS gene mutations (KRAS and NRAS) on tumor tissue obtained from a recent colonoscopic biopsy or metastatic site core biopsy. The clinical workflow includes: pathology confirmation of tumor specimen and selection of an appropriate tissue block, submission of the specimen to a molecular diagnostics laboratory, performance of validated PCR- or NGS-based RAS mutation analysis, review of results by the molecular pathologist, and transmission of the report to the treating oncologist to guide therapy selection. Testing is typically performed in an outpatient oncology clinic or hospital outpatient laboratory, with billing for the test recorded under HCPCS Level II code G9840 when applicable. Patient consent for molecular testing and documentation of medical necessity for targeted therapy selection are included in the medical record.

Coding Specifications

Modifier	Description	When to Use
`22`	Increased procedural services

HCPCS G9620: No Uterine Malignancy Screening or Endometrial Sampling

HCPCS-G9288-HISTOLOGY-CLASSIFICATION-NOT-REPORTED-REASON

HCPCS G9288: Documentation of Reason for Not Reporting Histologic Type

HCPCS-G0390-TRAUMA-RESPONSE-TEAM-HOSPITAL-CRITICAL-CARE

HCPCS G0390: Trauma Response Team for Hospital Critical Care

HCPCS-G9007-COORDINATED-CARE-TEAM-CONFERENCE

HCPCS G9007: Coordinated Care Fee for Scheduled Team Conference

HCPCS-G9236-OPTIMIZING-PATIENT-EXPOSURE-IONIZING-RADIATION-MEASURES-COMPLETED

HCPCS G9236: Optimization of Patient Exposure to Ionizing Radiation

HCPCS-G9664-STATIN-THERAPY-USER-OR-PRESCRIPTION

HCPCS G9664: Statin Therapy User or Statin Prescription

HCPCS-G9805-HOSPICE-SERVICES-MEASUREMENT-PERIOD

HCPCS G9805: Hospice Services During Measurement Period

HCPCS-G9674-CLINICAL-ASCVD-PATIENTS

HCPCS G9674: Patients with Clinical ASCVD Diagnosis

HCPCS-G9092-RECTAL-CANCER-DISEASE-STATUS-T1-3-N1-2-M0

HCPCS G9092: Rectal Cancer Disease Status, t1-3 n1-2 m0

HCPCS-G0039-PATIENT-NOT-REFERRED-ADMINISTRATIVE-REFERRAL-STATUS

HCPCS G0039: Patient Not Referred, Reason NOS

Showing 1–10 of 1996

Taxonomy Code	Specialty	Notes
`208000000X`	Hematology & Medical Oncology	Oncologists order RAS testing to guide anti-EGFR therapy decisions.
`207Q00000X`	Pathology	Pathologists select and submit tissue samples for molecular testing and interpret pathology reports.
`363L00000X`	Clinical Laboratory	Clinical laboratory directors oversee molecular assays and reporting.
`208D00000X`	Surgical Oncology	Surgeons obtain diagnostic or metastatic tissue enabling RAS testing.
`364SP0800X`	Molecular Pathology	Molecular pathologists perform and interpret RAS mutation analyses.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`C18.9`	Malignant neoplasm of colon, unspecified	Primary colorectal cancer diagnosis for which RAS testing guides anti-EGFR therapy.
`C19`	Malignant neoplasm of rectosigmoid junction	Tumors in this location are managed similarly and require RAS testing when metastatic.
`C20`	Malignant neoplasm of rectum	Rectal adenocarcinoma with metastatic disease may require RAS mutation assessment prior to targeted therapy.
`C78.7`	Secondary malignant neoplasm of liver and intrahepatic bile duct	Common metastatic site; biopsy of liver metastasis often provides tissue for RAS testing.
`C79.81`	Secondary malignant neoplasm of brain	Metastatic disease site where mutation testing on sampled tissue may be performed to guide systemic therapy.
`Z85.038`	Personal history of malignant neoplasm of large intestine	History code that may be present in surveillance or recurrence workups prompting molecular testing.
`Z51.11`	Encounter for antineoplastic chemotherapy	Indicates active systemic therapy planning where RAS status informs selection of anti-EGFR agents.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`81275`	KRAS (v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog) gene analysis; codon 12 and 13 (eg, common hotspot testing)	Often performed as initial single-gene hotspot testing for RAS status prior to broader RAS panel or targeted therapy decision.
`81276`	KRAS gene analysis; extended mutation analysis including codons 59, 61, 117, and 146	Used when extended KRAS testing beyond codons 12/13 is clinically indicated to fully assess RAS activating mutations.
`81304`	NRAS (neuroblastoma RAS viral oncogene homolog) gene analysis	Performed to detect NRAS activating mutations that also predict lack of response to anti-EGFR monoclonal antibodies.
`81479`	Unlisted molecular pathology procedure	Used when a specific RAS testing method or panel does not have an established CPT code and a lab bills an unlisted code.
`81445`	Oncology (somatic) hotspot mutation analysis by NGS single gene panel	Used when testing is performed via targeted NGS panels that include KRAS and NRAS hotspots as part of a multi-gene assay.
`88305`	Level IV surgical pathology, gross and microscopic examination	Performed by pathology to process and review biopsy specimens before sending tissue for molecular testing.

OpenPayer