Summary & Overview
CPT 81318: PMS2 Targeted Familial Mutation Analysis
CPT code 81318 denotes a targeted molecular diagnostic test performed by a laboratory to detect familial mutations in the PMS2 gene, a key DNA mismatch repair gene implicated in hereditary cancer syndromes. Nationally, precise detection of known familial PMS2 variants informs cascade testing, cancer risk assessment, and surveillance planning for at-risk relatives, making this code clinically significant in hereditary cancer care pathways. Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare.
Readers will find a concise overview of the clinical context for testing the PMS2 gene, an explanation of the service type and typical site of service, and what to expect in payer coverage landscapes. The publication outlines common billing considerations, frequently used modifiers, and national reimbursement and policy benchmarks where available. It also summarizes coding relationships and situates 81318 within molecular diagnostics workflows to help clinical laboratories and billing staff understand documentation and billing implications for targeted familial mutation analysis.
Billing Code Overview
CPT code 81318 describes a laboratory procedure in which a technical laboratory analysis is performed to detect the presence of mutations in the PMS2 gene (postmeiotic segregation increased 2 [S. cerevisiae]) that are known to be present in the patient’s family members. This is a targeted genetic test focusing on familial variants in the PMS2 DNA mismatch repair gene.
Service Type: Genetic testing — targeted mutation analysis
Typical Site of Service: Clinical molecular diagnostics laboratory or hospital pathology lab
Clinical & Coding Specifications
Clinical Context
A patient with a known family history of Lynch syndrome or a documented pathogenic variant in the PMS2 gene in a first‑ or second‑degree relative is referred for targeted genetic testing. Typical patients are adults or adolescents concerned about inherited colorectal, endometrial, or other Lynch‑associated cancer risk. The clinical workflow begins with genetic counseling to review family history, obtain informed consent, and collect a DNA specimen (usually peripheral blood or saliva). The specimen is sent to a molecular diagnostics laboratory where a lab analyst performs the targeted assay to detect the specific family‑identified PMS2 mutation using methods appropriate for PMS2 (e.g., long‑range PCR, MLPA, Sanger sequencing, or targeted NGS with pseudogene discrimination). Results are reported to the ordering clinician and genetic counselor for discussion of surveillance, cascade testing, and management. Typical site of service is an outpatient molecular diagnostic laboratory or hospital molecular pathology lab with specimen collection in an outpatient clinic, genetic counseling office, or phlebotomy center.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | Use when billing only the professional interpretation component if the performing laboratory separates technical and professional components. |
TC |