Summary & Overview
CPT 81328: SLCO1B1 Genetic Variant Testing
CPT code 81328 represents a molecular diagnostic laboratory test that detects specific variants in the SLCO1B1 gene, including common alleles such as *5. Nationally, this code is used to document laboratory-based pharmacogenomic testing that can inform drug transport and metabolism, particularly in medication management where SLCO1B1 variants affect drug exposure or risk of adverse effects. The code applies to clinical and reference laboratories performing targeted genotyping or sequencing for this single-gene marker.
Key payers included in this analysis are Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of the code’s clinical purpose, typical sites of service, and what to expect in payer coverage discussions. The publication also covers benchmarking context, common billing and documentation considerations, and clinical relevance for pharmacogenomics programs.
The content provides actionable background for coding staff, laboratory managers, and policy analysts who need to classify this molecular test correctly, understand where it is performed, and place it in clinical and billing workflows. Data not available in the input are noted where applicable.
Billing Code Overview
CPT code 81328 describes a laboratory test performed by a lab analyst to detect specific genetic changes in the SLCO1B1 gene, including common variants such as *5. The service is a molecular diagnostic assay focused on identifying single-gene variants that can affect drug transport and metabolism.
Service Type: Molecular diagnostic / Genetic testing
Typical Site of Service: Clinical laboratory or reference genetic testing 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 56-year-old patient with hyperlipidemia and a history of statin intolerance is referred for pharmacogenetic testing to evaluate SLCO1B1 common variants (for example, *5) that increase the risk of statin-associated myopathy. Blood or saliva is collected in the outpatient laboratory or clinic; the specimen is sent to a molecular genetics laboratory where a trained lab analyst performs technical testing using PCR-based genotyping or sequencing to detect SLCO1B1 variants. Results are reported to the ordering clinician and placed in the electronic health record to guide statin selection and dosing. Typical site of service is an outpatient clinic, physician office, or reference molecular laboratory; specimen collection may occur in a phlebotomy area or ambulatory collection center.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | Use when billing only the physician interpretation of the molecular test separate from the technical component. |
TC | Technical component | Use when billing only the laboratory technical component (testing performed by lab personnel) separate from interpretation. |