Summary & Overview
CPT 81327: SEPT9 Methylation Assay for Colorectal Cancer Detection
CPT code 81327 represents a laboratory molecular diagnostic assay that detects methylation of the SEPT9 gene promoter in circulating free DNA — a blood-based biomarker used in the evaluation and screening context for colorectal cancer. The test translates epigenetic detection into a minimally invasive option for identifying patients at increased risk of colorectal neoplasia, supporting earlier diagnostic follow-up and clinical decision-making.
This summary addresses national implications for payers including Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of clinical context, typical sites of service, and the role of the test in screening and diagnostic pathways. The publication also reviews payer coverage patterns, reimbursement benchmarks, and policy updates affecting laboratory molecular diagnostics, and explains operational considerations for labs and providers such as billing workflows and common modifiers.
Clinical stakeholders, laboratory directors, and billing professionals will learn how CPT code 81327 fits into current diagnostic algorithms for colorectal cancer, what commercial and public payers commonly cover, and where policy or coding guidance has recently evolved. Data not available in the input is clearly identified where applicable.
Billing Code Overview
CPT code 81327 describes a laboratory test performed on circulating free DNA in a patient’s blood to detect methylation of promoter regions that alter expression of the tumor suppressor gene Septin9 (SEPT9). The assay is used as a molecular biomarker for conditions such as colorectal cancer, detecting epigenetic changes associated with malignancy.
Service type: Laboratory — molecular diagnostic test (circulating tumor DNA methylation assay)
Typical site of service: Clinical laboratory or reference molecular diagnostics laboratory; sample collection performed in outpatient clinics or phlebotomy centers, with analysis in a certified lab
Clinical & Coding Specifications
Clinical Context
A 58-year-old average-risk adult presents for colorectal cancer screening and declines colonoscopy. The clinician orders a blood-based SEPT9 methylation assay to detect circulating tumor DNA associated with colorectal neoplasia. A phlebotomy specimen is collected in the outpatient laboratory, labeled, and shipped to the reference molecular laboratory. The laboratory analyst performs the technical assay to detect methylated promoter regions of the SEPT9 gene in cell-free DNA extracted from plasma. Results are reported to the ordering physician, who incorporates the result into shared decision-making about further diagnostic evaluation (for example, colonoscopy if test is positive). Typical site of service is outpatient clinic, hospital outpatient laboratory, or independent reference laboratory performing molecular diagnostic testing. Common clinical workflow steps: order entry, patient consent and specimen collection, accessioning and processing, molecular assay performance, result verification by laboratory personnel, and final report transmission to the ordering clinician.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | When reporting only the physician/pathologist interpretation if the laboratory charges separate technical and professional components. |
TC |