Summary & Overview
CPT 81374: HLA Class I Low/Intermediate-Resolution Testing
CPT code 81374 designates a laboratory technical test for low- or intermediate-resolution assessment of human leukocyte antigen (HLA) genes for one Class I antigen equivalent. This HLA allele-group testing supports clinical decision-making in contexts such as transplant matching, disease association studies, and pharmacogenomic risk assessment. Nationally, standardized reporting of such molecular diagnostic services affects laboratory billing consistency and payer coverage policies for genetic testing.
Key payers relevant to this service include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of the code’s clinical scope and typical sites of service, plus a summary of payer coverage considerations and common billing modifiers used with laboratory technical components. The publication outlines what to expect in coding and billing workflows, and provides context for how this test fits into broader genetic testing and transplant evaluation pathways.
This analysis is intended for a national audience and focuses on code definition, clinical context, and practical billing elements. Data not available in the input are explicitly noted where applicable.
Billing Code Overview
CPT code 81374 describes a laboratory technical service for low- or intermediate-resolution assessment of human leukocyte antigen (HLA) genes for one Class I antigen equivalent (an allele group of interest). The procedure typically involves laboratory analysis to identify HLA allele groups associated with specific clinical conditions or transplant compatibility.
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Service type: Laboratory genetic testing (technical component)
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Typical site of service: Clinical laboratory or hospital laboratory setting
Data not available in the input for payers, associated taxonomies, ICD-10 diagnoses, and related codes.
Clinical & Coding Specifications
Clinical Context
A 34-year-old adult with a history of recurrent transplant rejection evaluation is referred for HLA typing to determine suitability for organ transplantation and to identify donor–recipient compatibility. The clinician orders a low- or intermediate-resolution HLA class I allele group assay when preliminary HLA antigen group information is needed quickly for listing or for initial donor matching. A phlebotomy draw is performed in an outpatient blood draw center affiliated with a transplant center or hospital laboratory. The specimen is processed in a molecular immunogenetics laboratory where a technologist performs the technical portion of the assay, generating results for one Class I antigen equivalent (allele group of interest). The technical lab report is routed to the ordering transplant physician or transplant coordinator, who integrates the HLA result with clinical history, serologic testing, and, if required, higher-resolution typing or crossmatch testing. Typical sites of service include hospital clinical laboratories, independent reference laboratories, and transplant center laboratories. Workflow steps: obtain informed consent when required, collect specimen, accession and process sample, run HLA low/intermediate resolution assay for one Class I antigen equivalent, validate technical run, report results to ordering provider, and archive raw data according to laboratory policy.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | When billing only the professional interpretation of a separate technical lab test (rare for this code). |