Summary & Overview
CPT 81370: HLA Class I and II Low/Intermediate-Resolution Molecular Typing
CPT code 81370 denotes a laboratory technical service for low- or intermediate-resolution molecular typing of human leukocyte antigen (HLA) genes covering Class I (HLA–A, HLA–B, HLA–C) and Class II (HLA–DRB1, HLA–DRB3/4/5, HLA–DQB1). This test supports transplantation matching, immunogenetics evaluation, and select diagnostic workups where HLA typing informs clinical decisions. Nationally, standardized coding for HLA molecular testing matters for consistent reporting, claims processing, and aggregate monitoring of transplant-related services.
Key payers included in the analysis are Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of the clinical scope and service setting for the code, discussion of common billing considerations, and pointers to areas typically reviewed in coverage and reimbursement assessments such as technical component reporting and laboratory site of service. The publication covers benchmarking concepts, policy update considerations relevant to molecular HLA testing, and clinical context for when low- or intermediate-resolution typing is used. Data not available in the input are noted where applicable.
Billing Code Overview
CPT code 81370 describes a laboratory technical service for low- or intermediate-resolution molecular assessment of human leukocyte antigen (HLA) genes for Classes I and II. HLA Class I in this test includes HLA–A, HLA–B, and HLA–C. HLA Class II for this test includes HLA–DRB1, HLA–DRB3/4/5, and HLA–DQB1.
Service type: Laboratory molecular testing (technical component)
Typical site of service: Clinical laboratory or reference laboratory
Data not available in the input for associated taxonomies, ICD-10 diagnoses, and related codes.
Clinical & Coding Specifications
Clinical Context
A typical patient is a transplant candidate or recipient undergoing immunogenetic compatibility testing. For example, a 45-year-old patient being evaluated for kidney transplantation has a blood specimen collected in the outpatient lab. The clinical workflow includes: the ordering clinician (nephrologist or transplant coordinator) places an order for HLA typing; the phlebotomy team draws and properly labels the specimen; the specimen is sent to the molecular diagnostics laboratory; a laboratory analyst performs 81370 low or intermediate resolution molecular HLA Class I (HLA–A, –B, –C) and Class II (HLA–DRB1, –DRB3/4/5, –DQB1) testing; results are reviewed by laboratory personnel and reported into the electronic medical record; the transplant team uses results for donor–recipient matching and immunologic risk assessment. Typical site of service is an outpatient hospital laboratory, independent clinical molecular diagnostics laboratory, or a hospital-based transfusion/immunology laboratory. The typical service type is laboratory molecular testing using PCR-based or sequence-specific oligonucleotide/primer molecular techniques.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | Use when reporting only the professional interpretation component if applicable and billable separately. |
TC | Technical component | Use when billing only the technical component (laboratory processing and analysis). |
59 | Distinct procedural service | Use when an unrelated, separate procedure is performed on the same date and needs to be distinguished. |
90 | Reference (outside) laboratory | Use when the test was performed by an outside independent laboratory. |
91 | Repeat clinical diagnostic test | Use when repeat testing is performed on the same specimen to confirm unexpected results. |
52 | Reduced services | Use when the service is partially reduced or not completed as originally planned. |
53 | Discontinued procedure | Use when the testing process was started but discontinued. |
76 | Repeat procedure or service by same provider | 76 is not listed in input; use 91 instead. |
22 | Increased procedural services | Use when the test required substantially greater resources than typical (rare for standardized lab tests). |
90 | Reference (duplicate) | Duplicate entry avoided; only list once. |
| Taxonomy Code | Specialty | Notes |
|---|---|---|
| 2080S0001X | Clinical Molecular Laboratory Specialist | Specialists overseeing molecular HLA testing and result interpretation. |
| 207RC0000X | Clinical Laboratory | Clinical laboratory directors and supervisors responsible for testing quality and compliance. |
| 207L00000X | Clinical Pathology | Pathologists who may review complex immunogenetics results and provide consultative interpretation. |
| 3336C0002X | Transplant Coordinator | Ordering clinicians who manage donor/recipient testing workflow and documentation. |
| 207K00000X | Hematopathology | Laboratory specialists involved when testing intersects with hematology or transplant services. |
Related Diagnoses
| ICD-10 Code | Description | Clinical Relevance |
|---|---|---|
Z94.0 | Kidney transplant status | Common in patients undergoing HLA testing for donor matching or post-transplant monitoring. |
Z48.21 | Encounter for aftercare following kidney transplant | HLA testing may be used in surveillance and immunologic assessment. |
Z99.2 | Dependence on renal dialysis | Patients awaiting transplant often undergo HLA typing as part of evaluation. |
Z52.4 | Organ donor status | HLA typing is essential for donor evaluation and registries. |
D68.9 | Coagulation defect, unspecified | Hematologic conditions may necessitate immunogenetic workup in transplant or transfusion settings. |
Related CPT Codes
| CPT Code | Description | Relationship to This Procedure |
|---|---|---|
88381 | Consultation and review of cytogenetic or molecular test results (interpretation) | May be billed when a pathologist or molecular specialist provides a separate, billable interpretation of complex HLA results. |
86152 | Antibody identification, solid phase (e.g., Luminex) | Often performed alongside HLA typing for donor-specific antibody assessment in transplant evaluation. |
87220 | Culture, bacterial; presumptive identification by staining and microscopy | Not directly related to HLA typing; Data not available in the input. |
0000F | Data not applicable | Data not available in the input. |
81299 | Unlisted molecular pathology procedure | Used when a specific molecular HLA test falls outside established codes and requires an unlisted code. |
Note: Related code selection is based on common laboratory and transplant workflows. If specific institutional billing pathways differ, local coding guidance should be consulted.