Summary & Overview
CPT 81317: PMS2 Full-Gene Sequencing
CPT code 81317 covers full-gene sequencing of the PMS2 (postmeiotic segregation increased 2) gene performed by a laboratory analyst. Full-gene sequencing for PMS2 is a clinically significant molecular diagnostic service used to identify pathogenic variants associated with hereditary cancer syndromes and other genetic conditions that implicate mismatch repair. Nationally, accurate reporting of this code supports consistent billing, laboratory workflow documentation, and payer coverage decisions for high-complexity molecular testing.
Key payers discussed include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. The publication provides a concise national perspective on coding practice for PMS2 full-gene sequencing, expected sites of service, and common billing considerations.
Readers will learn: an overview of what CPT code 81317 represents; the clinical context for PMS2 sequencing; typical service settings where the test is performed; and practical information about common modifiers and billing components (listed separately). The piece also identifies where input data are not provided. This summary is intended for billing specialists, laboratory managers, and policy analysts seeking a national reference for CPT code 81317 in molecular diagnostics.
Billing Code Overview
CPT code 81317 describes laboratory analysis that sequences the entire coding region of the postmeiotic segregation increased 2 (PMS2) gene. The service involves a laboratory analyst performing the technical laboratory procedures required to generate and analyze sequence data for the PMS2 gene.
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Service type: Clinical molecular diagnostic sequencing
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Typical site of service: Clinical laboratory or specialized molecular diagnostics laboratory
Data not available in the input for payers, associated taxonomies, ICD-10 diagnoses, related codes, and service line.
Clinical & Coding Specifications
Clinical Context
A 42-year-old patient with a strong family history of Lynch syndrome–associated cancers is referred for germline genetic testing focused on the PMS2 gene. The clinician documents personal history of early-onset colorectal cancer in a first-degree relative and multiple colon polyps in the patient. A peripheral blood sample is collected in the outpatient phlebotomy lab and sent to a molecular diagnostics laboratory. The laboratory technologist performs complete gene sequencing of the PMS2 gene to detect single nucleotide variants, small insertions/deletions, and other sequence-level variants. The laboratory workflow includes DNA extraction, library preparation, next-generation sequencing (or Sanger sequencing for confirmatory testing), bioinformatic analysis, variant interpretation by a molecular pathologist, and final reporting. Results are routed to the ordering clinician, who discusses pathogenic or likely pathogenic findings with the patient and documents genetic counseling and recommended next steps in the medical record.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | Use when separate professional interpretation of test results by a pathologist or molecular geneticist is billed separately from the technical lab component. |
TC |