What is ICD-10 code D80.9?

D80.9 is the ICD-10-CM diagnosis code for Immunodeficiency with predominantly antibody defects, unspecified. 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). D80.9 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. D80.9 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. D80.9 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. D80.9 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 D80.9 map to under V28?

D80.9 has no payable CMS-HCC V28 mapping in the final FY2026 CMS file.

What RAF reference is published for D80.9?

D80.9 has no V28 reference coefficient because the final FY2026 source verifies no payable V28 mapping.

What is the V28 vs V24 difference for D80.9?

D80.9 has verified no payable V28 mapping in the final FY2026 source. Select a historical effective period before making any V24 comparison.

What documentation supports D80.9?

Use this code only when the documentation indicates an antibody deficiency but does not specify the type (such as IgA, IgG, or IgM deficiency); if a specific antibody deficiency is documented, use the more specific code instead This is an unspecified code (ending in .9), so query the provider if more specific information about the type of antibody defect is available in the medical record to ensure accurate coding D80.9 is not a CMS-HCC V28 payment code in the verified current source, so MEAT is not the payment hook. Documentation still has to support the diagnosis if you report it.

2026 ICD-10-CM D80.9: Immunodeficiency with predominantly

D80.9 is not a CMS-HCC payment code. MEAT criteria · RAF Calculator · free HCC coding tools

ICD-10-CM Code View

HCC Buddy Code Card

Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.

Code lookupD80.9

Effective 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)

D80.9

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

Immunodeficiency with predominantly antibody defects, unspecified

This code describes a condition where the immune system doesn't produce enough antibodies to fight infections, but the specific type of antibody deficiency is not specified. Patients with this condition are more susceptible to bacterial infections and may require immunoglobulin replacement therapy.

Buddy Insight

Overview Risk Models Code Book Documentation Audit Notes Edition comparison

CMS-HCC V28

N/A

—

Not risk-adjusted for this model/period.

Not mapped

CMS-HCC V24

Historical

Not used for standard CY2026 Medicare Advantage payment. Select a historical period to review V24.

Not used for CY2026 payment

ACA/HHS

Mapped

HCC 074

HHS-HCC 074 adult, RAF varies...

Code-level coefficient reference

ESRD/PACE

Mapped

HCC 47

Disorders of Immunity

Code-level coefficient reference

RXHCC

Mapped

HCC 99

Immune Disorders

Code-level coefficient reference

Code Book Path

Official

D80Immunodeficiency with predominantly antibody defects D80.9Immunodeficiency with predominantly antibody defects, unspecified

Inclusion Terms

Official

No inclusion terms are included in this display for D80.9. Check the code and parent instructions in the Code Book.

Excludes 2

Official

autoimmune disease (systemic) NOS (M35.9)Inherited from D50-D89
certain conditions originating in the perinatal period (P00-P96)Inherited from D50-D89
complications of pregnancy, childbirth and the puerperium (O00-O9A)Inherited from D50-D89
congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)Inherited from D50-D89
endocrine, nutritional and metabolic diseases (E00-E88)Inherited from D50-D89
human immunodeficiency virus [HIV] disease (B20)Inherited from D50-D89
injury, poisoning and certain other consequences of external causes (S00-T88)Inherited from D50-D89
neoplasms (C00-D49)Inherited from D50-D89
symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)Inherited from D50-D89

Related Codes

Official

D80.0Hereditary hypogammaglobulinemia D80.1Nonfamilial hypogammaglobulinemia D80.2Selective deficiency of immunoglobulin A [IgA]D80.3Selective deficiency of immunoglobulin G [IgG] subclasses D80.4Selective deficiency of immunoglobulin M [IgM]

Includes

Official

defects in the complement systemInherited from D80-D89
immunodeficiency disorders, except human immunodeficiency virus [HIV] diseaseInherited from D80-D89
sarcoidosisInherited from D80-D89

Excludes 1

Official

autoimmune disease (systemic) NOS (M35.9)Inherited from D80-D89
functional disorders of polymorphonuclear neutrophils (D71-)Inherited from D80-D89
human immunodeficiency virus [HIV] disease (B20)Inherited from D80-D89

Code First

Official

No Code First sequencing instructions are included in this display for D80.9. Check the code and parent instructions in the Code Book.

Use Additional

Official

No Use Additional Code instructions are included in this display for D80.9. Check the code and parent instructions in the Code Book.

Code Also

Official

No Code Also instructions are included in this display for D80.9. Check the code and parent instructions in the Code Book.

Buddy Documentation Tip

HCC Buddy guidance

Documentation should include evidence supporting an antibody deficiency diagnosis (recurrent infections, low immunoglobulin levels), the reason why further specificity is unavailable, and the plan for additional workup to characterize the defect.

Include any immunoglobulin levels tested and vaccine challenge responses if performed.

Query the provider for more specific information when possible.

MEAT Support

HCC Buddy guidance

Include any immunoglobulin levels tested and vaccine challenge responses if performed.

Query the provider for more specific information when possible.

Audit Caution

HCC Buddy guidance

This unspecified code should only be used when documentation genuinely lacks specificity about the type of antibody deficiency.

It is a high audit-risk code because reviewers will look for available immunological test results that might support a more specific code.

Never use this code when the medical record contains enough information to assign D80.0 through D80.8.

Common Mistakes

HCC Buddy guidance

D80.2 (selective Immunoglobulin A deficiency), D80.3 (selective Immunoglobulin G subclass deficiency), D80.4 (selective Immunoglobulin M deficiency), D83.9 (common variable immunodeficiency, unspecified, which requires CVID diagnostic criteria to be met), D84.9 (immunodeficiency, unspecified, an even broader code).

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 D80.9 an HCC code?

D80.9 is not in the CMS-HCC V28 or V24 community payment model. D80.9 has a separate mapping under the CMS-HCC ESRD model (HCC 47 (Disorders of Immunity)) and the Part D RxHCC model (HCC 99 (Immune Disorders)); the applicable result needs member context. D80.9 also appears in the HHS-HCC commercial risk model (HCC 074 (HHS-HCC 074 adult, RAF varies by metal level)), which is a commercial market model rather than a Medicare Advantage payment mapping.

Code: D80.9
Description: Immunodeficiency with predominantly antibody defects, unspecified
HCC (V28): No CMS-HCC V28 mapping
RAF reference coefficient: —
Billable: Yes
Payment year: 2026

HCC Category Mapping

ESRDHCC 47, Disorders of Immunity

Not separately weighted

RxHCCHCC 99, Immune Disorders

Not separately weighted

These are source-labeled model coefficients, not member totals. A category may still be removed by hierarchy or model cleanup rules. 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 context, hierarchy and cleanup rules, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains available for historical review.

Work D80.9 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT review for D80.9

For D80.9, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.

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

Coder workflow notes

Get the V28 mapping + MEAT cheat sheet

One printable reference: check representative V28 mappings and the documentation reminders your note needs. Free, no card.

Free PDF. No card. Unsubscribe anytime.

What This Code Means

D80.9 is the ICD-10-CM diagnosis code for immunodeficiency with predominantly antibody defects, unspecified. This code describes a condition where the immune system doesn't produce enough antibodies to fight infections, but the specific type of antibody deficiency is not specified. Patients with this condition are more susceptible to bacterial infections and may require immunoglobulin replacement therapy. D80.9 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).

D80.9 has no mapping under the CMS-HCC V28 or V24 community payment models. D80.9 has a separate mapping under the CMS-HCC ESRD model (HCC 47 (Disorders of Immunity)) and the Part D RxHCC model (HCC 99 (Immune Disorders)); the applicable result needs member context. D80.9 also appears in the HHS-HCC commercial risk model (HCC 074 (HHS-HCC 074 adult, RAF varies by metal level)), which is a commercial market model rather than a Medicare Advantage payment mapping. Do not assign V28 risk adjustment value from this page; verify the applicable model and payment year before using this code for risk adjustment.

Use this code only when the documentation indicates an antibody deficiency but does not specify the type (such as IgA, IgG, or IgM deficiency); if a specific antibody deficiency is documented, use the more specific code instead.

HCC Buddy maintains structured V28 and V24 mapping, source-labeled coefficient references, and MEAT documentation criteria for D80.9 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Use this code only when the documentation indicates an antibody deficiency but does not specify the type (such as IgA, IgG, or IgM deficiency); if a specific antibody deficiency is documented, use the more specific code instead
•This is an unspecified code (ending in .9), so query the provider if more specific information about the type of antibody defect is available in the medical record to ensure accurate coding

Clinical Significance

Immunodeficiency with predominantly antibody defects, unspecified, indicates that a patient has been diagnosed with an antibody-mediated immunodeficiency but the specific type has not been determined or documented. These patients typically present with recurrent bacterial infections and may require immunoglobulin replacement therapy pending further immunological characterization.

Documentation Requirements

✓Documentation should include evidence supporting an antibody deficiency diagnosis (recurrent infections, low immunoglobulin levels), the reason why further specificity is unavailable, and the plan for additional workup to characterize the defect.
✓Include any immunoglobulin levels tested and vaccine challenge responses if performed.
✓Query the provider for more specific information when possible.

Commonly Confused Codes

•D80.2 (selective Immunoglobulin A deficiency), D80.3 (selective Immunoglobulin G subclass deficiency), D80.4 (selective Immunoglobulin M deficiency), D83.9 (common variable immunodeficiency, unspecified, which requires CVID diagnostic criteria to be met), D84.9 (immunodeficiency, unspecified, an even broader code).