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Official Description

HLA Class I and II typing, low resolution (eg, antigen equivalents); HLA-A, -B, -C, -DRB1/3/4/5, and -DQB1

© Copyright 2026 American Medical Association. All rights reserved.

Common Language Description

The HLA Class I and II typing, low resolution (CPT® Code 81370) is a laboratory procedure that focuses on identifying specific human leukocyte antigens (HLAs) which are critical components of the immune system. The HLA system is part of the major histocompatibility complex (MHC), which plays a vital role in the body's ability to recognize its own cells and tissues, as well as to defend against foreign invaders such as pathogens and non-self cells. HLAs are located on the short arm of chromosome 6 and are categorized into two main classes: Class I and Class II. Class I HLAs, which include the loci HLA-A, HLA-B, and HLA-C, are particularly significant for immune responses, while Class II HLAs, which encompass loci such as DRB1, DRB3, DRB4, DRB5, and DQB1, are essential for the regulation of immune responses. Each locus can have multiple variants known as alleles, which are designated by a specific nomenclature that includes the locus name followed by an asterisk and a series of digits indicating the allele's specific group and further details. The low resolution typing performed under this code identifies antigen equivalents rather than specific alleles, which is useful in various clinical contexts, including organ transplantation and disease susceptibility assessments. The procedure typically involves molecular techniques such as polymerase chain reaction (PCR) and may utilize methods like PCR sequence specific priming (SSP) to amplify groups of alleles. This test is crucial for understanding an individual's immune profile and can aid in making informed medical decisions regarding treatments and interventions.

© Copyright 2026 Coding Ahead. All rights reserved.

1. Indications

The HLA Class I and II typing, low resolution (CPT® Code 81370) is indicated for various clinical scenarios where understanding an individual's HLA profile is essential. The following conditions and situations may warrant this testing:

  • Organ Transplantation: To assess compatibility between donors and recipients, reducing the risk of transplant rejection.
  • Autoimmune Diseases: To evaluate susceptibility or resistance to certain autoimmune conditions, aiding in diagnosis and management.
  • Infectious Diseases: To understand the immune response to infections and potential vulnerabilities.
  • Hematological Disorders: To assist in the diagnosis and treatment planning for blood-related diseases.
  • Genetic Counseling: To provide information on hereditary conditions and risks associated with HLA types.

2. Procedure

The procedure for HLA Class I and II typing, low resolution, involves several key steps to ensure accurate identification of antigen equivalents. The following outlines the procedural steps:

  • Step 1: Sample Collection - A sample of nucleated cells is obtained, typically from a blood draw or buccal swab. This sample serves as the source of DNA for the typing process.
  • Step 2: Cell Lysis and Protein Digestion - The collected cells undergo lysis to break down the cell membrane, followed by protein digestion to prepare the DNA for extraction. This step is crucial for isolating the genetic material needed for analysis.
  • Step 3: DNA Extraction - The DNA is extracted from the lysed cells using chemical or mechanical methods, ensuring that the genetic material is purified and ready for amplification.
  • Step 4: Polymerase Chain Reaction (PCR) - The extracted DNA is subjected to PCR, a technique that amplifies specific regions of the DNA that correspond to the HLA loci of interest. This amplification is essential for detecting the presence of specific alleles.
  • Step 5: Sequence Specific Priming (SSP) - PCR SSP is employed to utilize a panel of primer pairs that target groups of alleles for low resolution typing. This method allows for the identification of antigen equivalents rather than specific alleles.
  • Step 6: Analysis and Reporting - The results of the PCR amplification are analyzed to determine the HLA typing, which is then reported to the healthcare provider for clinical interpretation and decision-making.

3. Post-Procedure

After the HLA Class I and II typing procedure, there are no specific post-procedure care requirements for the patient, as the process is non-invasive and typically does not result in complications. However, it is important for healthcare providers to review the results carefully, as they can have significant implications for patient management, particularly in the context of organ transplantation and autoimmune disease treatment. Patients may be advised to follow up with their healthcare provider to discuss the results and any necessary next steps based on their HLA typing outcomes.

Short Descr HLA I & II TYPING LR
Medium Descr HLA CLASS I&II LOW HLA-A -B -C -DRB1/3/4/5&DQB
Long Descr HLA Class I and II typing, low resolution (eg, antigen equivalents); HLA-A, -B, -C, -DRB1/3/4/5, and -DQB1
Status Code Statutory Exclusion (from MPFS, may be paid under other methodologies)
Global Days XXX - Global Concept Does Not Apply
PC/TC Indicator (26, TC) 9 - Not Applicable
Multiple Procedures (51) 9 - Concept does not apply.
Bilateral Surgery (50) 9 - Concept does not apply.
Physician Supervisions 09 - Concept does not apply.
Assistant Surgeon (80, 82) 9 - Concept does not apply.
Co-Surgeons (62) 9 - Concept does not apply.
Team Surgery (66) 9 - Concept does not apply.
Diagnostic Imaging Family 99 - Concept Does Not Apply
CLIA Waived (QW) No
APC Status Indicator Service Paid under Fee Schedule or Payment System other than OPPS
Type of Service (TOS) 5 - Diagnostic Laboratory
Berenson-Eggers TOS (BETOS) T1H - Lab tests - other (non-Medicare fee schedule)
MUE 1
CCS Clinical Classification 234 - Pathology
90 Reference (outside) laboratory: when laboratory procedures are performed by a party other than the treating or reporting physician or other qualified health care professional, the procedure may be identified by adding modifier 90 to the usual procedure number.
59 Distinct procedural service: under certain circumstances, it may be necessary to indicate that a procedure or service was distinct or independent from other non-e/m services performed on the same day. modifier 59 is used to identify procedures/services, other than e/m services, that are not normally reported together, but are appropriate under the circumstances. documentation must support a different session, different procedure or surgery, different site or organ system, separate incision/excision, separate lesion, or separate injury (or area of injury in extensive injuries) not ordinarily encountered or performed on the same day by the same individual. however, when another already established modifier is appropriate it should be used rather than modifier 59. only if no more descriptive modifier is available, and the use of modifier 59 best explains the circumstances, should modifier 59 be used. note: modifier 59 should not be appended to an e/m service. to report a separate and distinct e/m service with a non-e/m service performed on the same date, see modifier 25.
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2013-01-01 Changed Medium Descriptor changed.
2012-01-01 Added Added
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