Combined immunodeficiencies (D81) ICD-10-CM
The D81 code range covers combined immunodeficiencies with 21 ICD-10-CM diagnosis codes. 17 of them are billable and valid for claim submission in fiscal year 2027, and the category headers group them but cannot themselves be billed.
Type 1 Excludes
A type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.
- autosomal recessive agammaglobulinemia Swiss type D80.0
Codes in the D81 Range 21 codes · 17 billable
- D81 Combined immunodeficienciesNon-billable
- D81.0 Severe combined immunodeficiency [SCID] with reticular dysgenesis
- D81.1 Severe combined immunodeficiency [SCID] with low T- and B-cell numbers
- D81.2 Severe combined immunodeficiency [SCID] with low or normal B-cell numbers
- D81.3 Adenosine deaminase [ADA] deficiencyNon-billable
- D81.30 Adenosine deaminase deficiency, unspecified
- D81.31 Severe combined immunodeficiency due to adenosine deaminase deficiency
- D81.32 Adenosine deaminase 2 deficiency
- D81.39 Other adenosine deaminase deficiency
- D81.4 Nezelof's syndrome
- D81.5 Purine nucleoside phosphorylase [PNP] deficiency
- D81.6 Major histocompatibility complex class I deficiency
- D81.7 Major histocompatibility complex class II deficiency
- D81.8 Other combined immunodeficienciesNon-billable
- D81.81 Biotin-dependent carboxylase deficiencyNon-billable
- D81.810 Biotinidase deficiency
- D81.818 Other biotin-dependent carboxylase deficiency
- D81.819 Biotin-dependent carboxylase deficiency, unspecified
- D81.82 Activated Phosphoinositide 3-kinase Delta Syndrome [APDS]
- D81.89 Other combined immunodeficiencies
- D81.9 Combined immunodeficiency, unspecified
Clinical Terms in This Code Range
Definitions from the National Library of Medicine for conditions coded in the D81 range.
Adenosine Deaminase 2 Deficiency
A disorder characterized by abnormal inflammation of various tissues, particularly the blood vessels, with intermittent. fevers, areas of net-like, mottled skin discoloration (livedo racemosa), hepatosplenomegaly, and recurrent strokes.
Adenosine Deaminase Deficiency
An autosomal recessive deficiency of the purine salvage enzyme adenosine deaminase which results in Severe Combined Immunodeficiency Disease (SCID). The most common form of SCID, accounting for about 50% of autosomal recessive cases. The first disease for which gene therapy was applied.
Biotinidase Deficiency
The late onset form of MULTIPLE CARBOXYLASE DEFICIENCY (deficiency of the activities of biotin-dependent enzymes propionyl-CoA carboxylase, methylcrotonyl-CoA carboxylase, and PYRUVATE CARBOXYLASE) due to a defect or deficiency in biotinidase which is essential for recycling BIOTIN.
About the D81 Code Range
Combined immunodeficiencies include severe combined immunodeficiency, adenosine deaminase deficiency, and other named conditions.
The severe combined immunodeficiency codes distinguish low T- and B-cell numbers from low or normal B-cell numbers. Within D81.3, adenosine deaminase deficiency is divided into unspecified, severe combined immunodeficiency due to that deficiency, adenosine deaminase 2 deficiency, and other forms.
The codes also separate major histocompatibility complex class I deficiency from class II deficiency. Under D81.8, biotin-dependent carboxylase deficiency has subdivisions for biotinidase deficiency, other forms, and unspecified deficiency. Activated Phosphoinositide 3-kinase Delta Syndrome and other combined immunodeficiencies appear in this branch. D81.9 identifies combined immunodeficiency without a specified type.
Questions About This Page
How many billable codes are in the D81 range?
Of the 21 codes in this range, 17 are billable and valid for claim submission from October 1, 2026 through September 30, 2027. Category header codes group them but cannot be reported on claims.
What does the D81 range classify?
The range classifies combined immunodeficiencies. Each code links to its own reference page with billing status, MS-DRG grouping, coding notes, and clinical information.
Related References
Source: CMS FY 2027 ICD-10-CM Tabular List and order file, effective October 1, 2026 through September 30, 2027.
