Summary & Overview
CPT 81381: HLA High-Resolution Test for One Class I Allele
CPT code 81381 denotes a high-resolution laboratory assay for human leukocyte antigen (HLA) genes targeting one Class I allele or allele group. This code captures the technical laboratory work to determine allele-level HLA variation that can be clinically relevant for transplantation compatibility, disease association studies, and pharmacogenomic considerations. Nationally, detailed HLA typing is an important component of precision medicine and transplant workflows, where allele-level resolution can affect donor selection and patient management.
Key payers in the analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find an overview of clinical context and typical sites of service, a synopsis of payer coverage patterns and common modifiers, and benchmarks related to utilization and reimbursement practice where available. The publication also outlines coding relationships and service-line placement for laboratory molecular diagnostics.
Readers will learn how CPT code 81381 is positioned within laboratory service catalogs, the practical implications for service delivery in clinical laboratories, and the types of clinical scenarios that commonly prompt ordering of high-resolution HLA Class I allele testing. Data not available in the input is noted where applicable.
Billing Code Overview
CPT code 81381 describes a high-resolution laboratory assessment of human leukocyte antigen (HLA) genes for a single Class I allele or allele group of interest. The procedure is performed by a laboratory analyst who carries out the technical testing to resolve HLA allele-level variation, typically focused on one allele or allele group associated with a specific clinical condition.
Service type: Laboratory — molecular/genetic testing (technical component).
Typical site of service: Clinical laboratory or hospital-based molecular diagnostics laboratory.
Clinical & Coding Specifications
Clinical Context
A 32-year-old woman with a history of recurrent pregnancy loss is referred to a reproductive immunology clinic for high-resolution human leukocyte antigen (HLA) typing of a single Class I allele associated with alloimmune incompatibility. Blood is drawn in the clinic and sent to a molecular diagnostics lab. The laboratory analyst performs high-resolution sequence-based typing for the specific Class I HLA allele of interest, processes raw sequencing data, and reports allele-level results to the ordering clinician. Results support partner compatibility assessment, transplant-related donor selection, or evaluation of HLA-associated drug hypersensitivity risk.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
00 | No modifier — standard billing | Use when no specific modifier applies for the service provided |
26 | Professional component | Use when billing only the professional interpretation portion of the test if separate from the laboratory technical component |
TC |