What is ICD-10 code D81.32?

D81.32 is the ICD-10-CM diagnosis code for Adenosine deaminase 2 deficiency. It belongs to the ICD-10-CM chapter for diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism (d50-d89). D81.32 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. D81.32 is part of the FY2026 ICD-10-CM code set published by the CMS National Center for Health Statistics and used on Medicare, Medicaid, and commercial claims in the United States.

Yes. D81.32 is a billable ICD-10-CM code that can be reported on professional and institutional claims as a primary or secondary diagnosis when the provider documentation supports the specific condition described. Billable codes in ICD-10-CM are coded to the highest level of specificity available for the documented diagnosis. D81.32 is current for fiscal year 2026 and remains in the active CMS ICD-10-CM code set published by the National Center for Health Statistics.

Which HCC does D81.32 map to under V28?

D81.32 maps to CMS-HCC V28 114 (Common Variable and Combined Immunodeficiencies). The category number and label come from the CMS-HCC V28 model file for payment year 2026.

What does D81.32 pay in RAF?

D81.32 carries a community, non-dual, aged (CNA) RAF weight of 2.262 under CMS-HCC V28 for payment year 2026. The weight comes from the CMS V28 relative-factor file, not a hand-typed table.

What is the V28 vs V24 difference for D81.32?

CMS phased in the V28 risk adjustment model over payment years 2024 (33%), 2025 (67%), and 2026 (100%), replacing V24. V28 consolidates HCC categories, removes some lower-acuity conditions, and recalibrates RAF weights across the entire model. For D81.32, V28 maps to Common Variable and Combined Immunodeficiencies at RAF 2.262 while V24 mapped to Disorders of Immunity at RAF 0.665. Both models can still appear in legacy data and in payer-specific lookback periods.

What documentation supports D81.32?

This is a specific subtype of adenosine deaminase deficiency - ensure you use D81.32 rather than the more general code D81.3 to capture the precise enzyme deficiency This condition is often diagnosed in infancy or early childhood; verify documentation confirms ADA2 deficiency specifically and look for associated complications like recurrent infections or inflammatory manifestations that may require additional coding Because D81.32 maps to a payment HCC, the documentation must also satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's risk adjustment score. See the MEAT criteria checklist at /meat-criteria for what Monitor, Evaluate, Assess, or Treat looks like in a note. MEAT is generic documentation evidence, not a payer-specific rule.

2026 ICD-10-CM D81.32: Adenosine deaminase 2

D81.32 maps to CMS-HCC V28 114 (RAF 2.262). Documentation must support MEAT. MEAT criteria · RAF calculator · free HCC coding tools

ICD-10-CM Code View

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Code lookupD81.32Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism (D50-D89) / Certain disorders involving the immune mechanism (D80-D89)

D81.32

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Adenosine deaminase 2 deficiency

This is a rare genetic disorder where the body lacks an enzyme called adenosine deaminase 2, which normally helps break down certain substances in cells. This deficiency causes problems with the immune system and can lead to inflammation and infections.

Buddy Insight

Adenosine deaminase 2 deficiency is a distinct autoinflammatory and immunodysregulatory disorder caused by mutations in the CECR1/ADA2 gene.

CMS-HCC V28

Mapped

HCC 114

Common Variable and Combined ...

RAF 2.262

CMS-HCC V24

Mapped

HCC 47

Disorders of Immunity

RAF 0.665

ACA/HHS

Mapped

HCC 73

HHS-HCC 73

Varies by metal level

ESRD/PACE

Mapped

HCC 47

Disorders of Immunity

RAF 0.078

RXHCC

Mapped

HCC 99

Immunodeficiencies

RAF 0.943

Code Book Path

Official

D81Combined immunodeficiencies

D81.3Adenosine deaminase [ADA] deficiency

D81.32Adenosine deaminase 2 deficiency

Inclusion Terms

Official

ADA2 deficiency
Adenosine deaminase deficiency type 2

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for D81.32 in this effective period.

Related Child Codes

Official

D81.30Adenosine deaminase deficiency, unspecified

D81.31Severe combined immunodeficiency due to adenosine deaminase deficiency

D81.39Other adenosine deaminase deficiency

Includes

Official

ICD-10-CM does not list Includes notes for D81.32 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for D81.32 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for D81.32 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for D81.32 in this effective period.

Code Also

Official

, if applicable, any associated manifestations, such as:
polyarteritis nodosa (M30.0)
stroke (I63.-)

Buddy Documentation Tip

HCC Buddy guidance

Documentation must include genetic testing confirming CECR1/ADA2 gene mutation, adenosine deaminase 2 enzyme activity levels, clinical manifestations including vasculitis, stroke history, liver and spleen assessment, immunoglobulin levels, complete blood count showing cytopenias, and treatment plan.

Document any history of lacunar strokes, livedo racemosa, or hepatosplenomegaly that are hallmark features.

MEAT Support

HCC Buddy guidance

Document any history of lacunar strokes, livedo racemosa, or hepatosplenomegaly that are hallmark features.

Audit Caution

HCC Buddy guidance

This is a fundamentally different condition from adenosine deaminase 1 deficiency despite the similar naming.

Adenosine deaminase 2 deficiency presents as vasculitis and autoinflammation rather than SCID.

Do not default to D81.30 or D81.31 for this condition.

Additional codes should be assigned for specific manifestations such as stroke (I63 series), vasculitis, or cytopenias.

Common Mistakes

HCC Buddy guidance

D81.31 (severe combined immunodeficiency due to adenosine deaminase 1 deficiency, a completely different enzyme and clinical presentation), D81.30 (adenosine deaminase deficiency, unspecified), M30.0 (polyarteritis nodosa, which adenosine deaminase 2 deficiency can mimic), D81.39 (other adenosine deaminase deficiency for non-SCID adenosine deaminase 1 deficiency).

Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →

Is D81.32 an HCC code?

Yes. D81.32 (Adenosine deaminase 2 deficiency) maps to Common Variable and Combined Immunodeficiencies under the CMS-HCC V28 risk adjustment model (and Disorders of Immunity under V24), with a community non-dual aged RAF of 2.262. It is billable for payment year 2026.

Coder answer: D81.32 is billable and maps to V28 HCC 114, Common Variable and Combined Immunodeficiencies. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code: D81.32
Description: Adenosine deaminase 2 deficiency
HCC (V28): HCC 114 — Common Variable and Combined Immunodeficiencies
RAF: 2.262
Billable: Yes
Payment year: 2026

HCC Category Mapping

V28HCC 114, Common Variable and Combined Immunodeficiencies

2.262

V24HCC 47, Disorders of Immunity

0.665

ESRDHCC 47, Disorders of Immunity

0.078

RxHCCHCC 99, Immunodeficiencies

0.943

Each model's RAF is its CMS base weight for that model's standard population, so weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.

Work D81.32 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for D81.32

For D81.32 to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically, it has to be re-documented and supported each calendar year.

MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
EEvaluate: test results, medication response, or physical findings reviewed by the provider
AAssess: explicit mention in the assessment or plan with acknowledgment of status
TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis

Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed D81.32 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

D81.32 is the ICD-10-CM diagnosis code for adenosine deaminase 2 deficiency. This is a rare genetic disorder where the body lacks an enzyme called adenosine deaminase 2, which normally helps break down certain substances in cells. This deficiency causes problems with the immune system and can lead to inflammation and infections. D81.32 sits in the ICD-10-CM chapter for diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism (d50-d89), within the section covering certain disorders involving the immune mechanism (d80-d89).

Under the CMS-HCC V28 risk adjustment model, D81.32 maps to Common Variable and Combined Immunodeficiencies (HCC 114) with a community, non-dual, aged base RAF weight of 2.262. Under the older CMS-HCC V24 model, D81.32 maps to Disorders of Immunity (HCC 47) with a community, non-dual, aged base RAF weight of 0.665. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.

This is a specific subtype of adenosine deaminase deficiency - ensure you use D81.32 rather than the more general code D81.3 to capture the precise enzyme deficiency. Because D81.32 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.

HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for D81.32 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•This is a specific subtype of adenosine deaminase deficiency - ensure you use D81.32 rather than the more general code D81.3 to capture the precise enzyme deficiency
•This condition is often diagnosed in infancy or early childhood; verify documentation confirms ADA2 deficiency specifically and look for associated complications like recurrent infections or inflammatory manifestations that may require additional coding

Clinical Significance

Adenosine deaminase 2 deficiency is a distinct autoinflammatory and immunodysregulatory disorder caused by mutations in the CECR1/ADA2 gene. Unlike adenosine deaminase 1 deficiency, this condition primarily manifests with systemic vasculitis resembling polyarteritis nodosa, recurrent strokes, hepatosplenomegaly, and variable immunodeficiency including hypogammaglobulinemia and cytopenias rather than classic SCID.

Documentation Requirements

✓Documentation must include genetic testing confirming CECR1/ADA2 gene mutation, adenosine deaminase 2 enzyme activity levels, clinical manifestations including vasculitis, stroke history, liver and spleen assessment, immunoglobulin levels, complete blood count showing cytopenias, and treatment plan.
✓Document any history of lacunar strokes, livedo racemosa, or hepatosplenomegaly that are hallmark features.

Code Also

, if applicable, any associated manifestations, such as:
polyarteritis nodosa (M30.0)
stroke (I63.-)

Commonly Confused Codes

•D81.31 (severe combined immunodeficiency due to adenosine deaminase 1 deficiency, a completely different enzyme and clinical presentation), D81.30 (adenosine deaminase deficiency, unspecified), M30.0 (polyarteritis nodosa, which adenosine deaminase 2 deficiency can mimic), D81.39 (other adenosine deaminase deficiency for non-SCID adenosine deaminase 1 deficiency).