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ICD-10 Guide
ICD-10 CodesD81.6

D81.6

Billable

Major histocompatibility complex class I deficiency

BILLABLE STATUSYes
IMPLEMENTATION DATEOctober 1, 2015
LAST UPDATED09/05/2025

Code Description

ICD-10 D81.6 is a billable code used to indicate a diagnosis of major histocompatibility complex class i deficiency.

Key Diagnostic Point:

Major histocompatibility complex class I (MHC I) deficiency is a rare immunological disorder characterized by the absence or dysfunction of MHC I molecules on the surface of cells. These molecules play a crucial role in the immune system by presenting peptide fragments derived from intracellular proteins to CD8+ T cells, which are essential for the recognition and elimination of infected or malignant cells. Patients with MHC I deficiency are prone to recurrent viral infections, particularly from cytomegalovirus (CMV) and other herpesviruses, due to their impaired ability to mount an effective cytotoxic T cell response. The condition can be inherited in an autosomal recessive manner and may present in infancy or early childhood. Clinical manifestations can include failure to thrive, recurrent respiratory infections, and chronic skin lesions. Diagnosis typically involves genetic testing to identify mutations in the genes responsible for MHC I expression, along with immunological assays to assess T cell function. Management focuses on preventing infections, which may include prophylactic antiviral therapy and, in severe cases, hematopoietic stem cell transplantation.

Code Complexity Analysis

Complexity Rating: High

High Complexity

Complexity Factors

  • Rare condition with limited awareness among healthcare providers
  • Requires detailed immunological and genetic testing documentation
  • Potential for overlapping symptoms with other immunodeficiencies
  • Need for comprehensive patient history to establish diagnosis

Audit Risk Factors

  • Insufficient documentation of genetic testing results
  • Lack of detailed immunological assessment in medical records
  • Inconsistent use of the code across different providers
  • Failure to document recurrent infections adequately

Specialty Focus

Medical Specialties

Immunology

Documentation Requirements

Thorough documentation of immunological tests, genetic testing results, and clinical history of infections.

Common Clinical Scenarios

Patients presenting with recurrent viral infections and failure to thrive.

Billing Considerations

Ensure all relevant laboratory results are included in the medical record to support the diagnosis.

Hematology

Documentation Requirements

Detailed records of any hematopoietic stem cell transplant procedures and follow-up care.

Common Clinical Scenarios

Management of patients with severe MHC I deficiency requiring transplantation.

Billing Considerations

Document any complications related to hematopoietic stem cell transplantation.

Coding Guidelines

Inclusion Criteria

Use D81.6 When
  • Follow the official ICD
  • CM coding guidelines for immunodeficiencies
  • Ensure that the diagnosis is supported by appropriate clinical documentation, including laboratory results and patient history

Exclusion Criteria

Do NOT use D81.6 When
  • Exclude other similar conditions before assigning this code

Related ICD-10 Codes

Related CPT Codes

88305CPT Code

Pathology consultation for immunological testing

Clinical Scenario

Used when evaluating a patient for MHC I deficiency.

Documentation Requirements

Documentation of the clinical rationale for testing and results interpretation.

Specialty Considerations

Immunologists should ensure comprehensive documentation of all tests performed.

ICD-10 Impact

Diagnostic & Documentation Impact

Enhanced Specificity

ICD-10 Improvements

The transition to ICD-10 has allowed for more specific coding of rare immunodeficiencies like MHC I deficiency, improving the accuracy of data collection and reimbursement processes.

ICD-9 vs ICD-10

The transition to ICD-10 has allowed for more specific coding of rare immunodeficiencies like MHC I deficiency, improving the accuracy of data collection and reimbursement processes.

Reimbursement & Billing Impact

reimbursement processes.

Resources

Clinical References

  • •
    American Academy of Allergy, Asthma & Immunology

Coding & Billing References

  • •
    American Academy of Allergy, Asthma & Immunology

Frequently Asked Questions

What are the common symptoms of MHC I deficiency?

Common symptoms include recurrent viral infections, failure to thrive, and chronic skin lesions. Patients may also experience severe infections from common viruses like CMV.