D81.6Billable
Major histocompatibility complex class I deficiency
- Chapter
- 3. Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism
- Category
- D81
- Effective date
- October 1, 2026
Related codes in category D81
D81Combined immunodeficienciesD81.0Severe combined immunodeficiency with reticular dysgenesisYesD81.1Severe combined immunodeficiency w low T- and B-cell numbersYesD81.2Severe combined immunodef w low or normal B-cell numbersYesD81.3Adenosine deaminase [ADA] deficiencyD81.30Adenosine deaminase deficiency, unspecifiedYesD81.31Severe combined immunodef due to adenosine deaminase deficYesD81.32Adenosine deaminase 2 deficiencyYesD81.39Other adenosine deaminase deficiencyYesD81.4Nezelof's syndromeYesD81.5Purine nucleoside phosphorylase [PNP] deficiencyYesD81.7Major histocompatibility complex class II deficiencyYes
Frequently asked questions
What is ICD-10 code D81.6?
D81.6 is an ICD-10-CM diagnosis code for Major histocompatibility complex class I deficiency.
Is D81.6 a billable code?
Yes. D81.6 is billable and specific enough to be used on a claim.
What ICD-10-CM chapter is D81.6 in?
D81.6 falls under Chapter 3: Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism.
When did D81.6 become effective?
D81.6 has been effective since October 1, 2026, per the CMS/CDC ICD-10-CM annual release.
What other codes are related to D81.6?
D81.6 belongs to category D81, which includes 12 other codes — see the related codes list on this page.
ICD-10-CM data maintained by CDC/CMS (public domain). Always verify codes with authoritative sources before making coding or billing decisions.