S3866 Genetic Analysis (HCPCS) Reimbursement

HCPCS Level II code S3866 denotes targeted genetic analysis to detect a known familial mutation associated with hypertrophic cardiomyopathy (HCM). This code captures a precision diagnostic service used in cascade testing when a pathogenic HCM variant has been identified in a family member. Nationally, such testing supports early identification of at-risk individuals, informs clinical surveillance, and can affect care pathways for cardiology and genetics services.

Key payers in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find an overview of coverage considerations across major payers, common billing modifiers associated with laboratory and professional components, and clinical context for when targeted familial HCM testing is applied. The publication also summarizes typical sites of service and the role of this test in cascade genetic screening.

The report does not provide state-specific policy details. It highlights benchmarks and policy updates relevant to payment and coding for targeted genetic tests, explains the clinical rationale for familial mutation testing in HCM, and identifies gaps where payer guidance or coding specificity may be limited.

Billing Code Overview

HCPCS Level II code S3866 describes genetic analysis for a specific gene mutation related to hypertrophic cardiomyopathy (HCM) performed for an individual with a known HCM mutation in the family. This service involves targeted molecular testing to identify whether the individual carries the familial HCM pathogenic variant.

Service type: Genetic testing / targeted molecular diagnostic testing
Typical site of service: Outpatient laboratory or clinical genetics service (e.g., hospital outpatient laboratory, independent genetic testing laboratory, or clinician office with specimen sent to a lab)

Data not available in the input.

Clinical Context

A 28-year-old individual with a first-degree relative recently diagnosed with hypertrophic cardiomyopathy (HCM) and a confirmed pathogenic mutation presents for targeted genetic testing. The patient has a family history of sudden cardiac death and mild exertional dyspnea but no definitive left ventricular hypertrophy on echocardiography. The clinical workflow begins with a cardiology visit where family history is documented and genetic counseling is provided. After informed consent, a blood or saliva specimen is collected in the outpatient genetics laboratory or an ambulatory phlebotomy clinic. The laboratory performs targeted sequence analysis or single-site mutation testing for the known familial HCM variant. Results are reported to the ordering cardiologist and genetic counselor; positive findings prompt cascade testing recommendations for relatives and may influence surveillance frequency, lifestyle guidance, and consideration of implantable cardioverter-defibrillator (ICD) evaluation. Typical site of service: outpatient clinic, genetics laboratory, or ambulatory phlebotomy collection site. Service type: targeted single-gene genetic analysis for a known familial HCM mutation, coded by S3866.

Coding Specifications

Modifier	Description	When to Use
`26`	Professional component	Use when billing physician professional interpretation separate from the lab technical component.

Taxonomy Code	Specialty	Notes
207RG0100X	Cardiology	Ordering cardiologists evaluate HCM and coordinate genetic testing and follow-up.
2080P0207X	Medical Genetics & Genomics	Clinical geneticists or genetic counselors provide test selection, counseling, and result interpretation.
363A00000X	Laboratory Genetic Testing	Laboratory geneticists and molecular pathology labs perform the targeted mutation analysis.
208D00000X	Neurology (Cardiac electrophysiology overlap)	Electrophysiologists consult for arrhythmia risk assessment when results influence ICD decisions.
363L00000X	Clinical Laboratory	Phlebotomy and specimen processing staff operate under this taxonomy.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`I42.1`	Obstructive hypertrophic cardiomyopathy	Primary clinical diagnosis prompting targeted familial genetic testing.
`I42.2`	Other hypertrophic cardiomyopathy	Covers nonobstructive forms; indicates need for genetic evaluation.
`I42.8`	Other cardiomyopathies	Used when cardiomyopathy subtype is unspecified but genetic testing is considered.
`Z15.01`	Genetic susceptibility to malignant neoplasm of breast	Data not directly related to HCM; include only if multisyndromic testing or panels detect incidental findings.
`Z13.79`	Encounter for screening for other genetic and chromosomal anomalies	Used for asymptomatic family members undergoing targeted familial mutation screening.
`Z80.2`	Family history of malignant neoplasm of the breast	Not directly HCM-related; not typically used for HCM testing but may appear when family history prompts broader genetic evaluation.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`81479`	Unlisted molecular pathology procedure	May be used by laboratories to report a targeted single-site or novel molecular test when no specific CPT exists.
`81291`	`MYBPC3` (myosin binding protein C) gene analysis; full gene sequence analysis	Related when comprehensive sequencing of common HCM genes is performed after or instead of targeted family variant testing.
`81406`	Hereditary breast cancer panel including BRCA1/BRCA2, etc.	Not directly related to HCM testing; included here as an example of multigene panel coding practices when expanded cardiomyopathy panels are run (use when broader inherited cardiomyopathy panels are performed).
`88305`	Level IV surgical pathology, gross and microscopic examination	Used when tissue (rarely) is submitted and requires pathology review; generally not applicable for standard blood-based genetic testing.
`99213`	Office or other outpatient visit, established patient, low to moderate complexity	Used for pre-test counseling, consent, and result disclosure visits in the outpatient setting.

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Summary & Overview

HCPCS S3866: Genetic Analysis for Familial Hypertrophic Cardiomyopathy Mutation