What is ICD-10 code D89.3?

D89.3 is the ICD-10-CM diagnosis code for Immune reconstitution syndrome. A syndrome that occurs when the immune system rapidly recovers after being suppressed, causing inflammation and tissue damage, often seen in HIV/AIDS patients starting antiretroviral therapy. D89.3 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. D89.3 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. D89.3 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. D89.3 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 D89.3 map to under V28?

D89.3 has no payable CMS-HCC V28 mapping in the final FY2026 CMS file.

What RAF reference is published for D89.3?

D89.3 has no V28 reference coefficient because the final FY2026 source verifies no payable V28 mapping.

What is the V28 vs V24 difference for D89.3?

D89.3 has verified no payable V28 mapping in the final FY2026 source. Select a historical effective period before making any V24 comparison.

What documentation supports D89.3?

This code is commonly used in immunocompromised patients, particularly those with HIV starting treatment Document the specific manifestations and affected organs for complete clinical picture D89.3 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.

Can D89.3 be a primary diagnosis?

Yes. D89.3 carries no code-first instruction in the FY2026 tabular, so it can be the first-listed diagnosis when it is the condition chiefly responsible for the encounter and the note supports it, and it can also be reported as a secondary diagnosis. For risk adjustment the order does not matter; the V28 category is the same either way.

Which codes cannot be reported with D89.3?

The Excludes1 note that applies to D89.3 lists autoimmune disease (systemic) NOS (M35.9); functional disorders of polymorphonuclear neutrophils (D71-); human immunodeficiency virus [HIV] disease (B20); hyperglobulinemia NOS (R77.1); and 1 more (see the notes on this page). An Excludes1 condition is not reported together with D89.3; report one or the other, unless the two conditions are unrelated, which the ICD-10-CM Official Guidelines (Section I.A.12.a) allow. The Excludes2 note lists autoimmune disease (systemic) NOS (M35.9); certain conditions originating in the perinatal period (P00-P96); complications of pregnancy, childbirth and the puerperium (O00-O9A); congenital malformations, deformations and chromosomal abnormalities (Q00-Q99); and 6 more (see the notes on this page); those are separate conditions that may be reported together with D89.3 when both are documented.

2026 ICD-10-CM D89.3: Immune reconstitution syndrome

D89.3 is not a CMS-HCC payment code. MEAT criteria · RAF Calculator · free HCC coding tools

ICD-10-CM Code View

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Code lookupD89.3

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)

D89.3

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

Immune reconstitution syndrome

A syndrome that occurs when the immune system rapidly recovers after being suppressed, causing inflammation and tissue damage, often seen in HIV/AIDS patients starting antiretroviral therapy.

Buddy Insight

Immune reconstitution inflammatory syndrome occurs when a recovering immune system mounts an excessive inflammatory response to previously acquired infections or antigens.

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

D89Other disorders involving the immune mechanism, not elsewhere classified D89.3Immune reconstitution syndrome

Inclusion Terms

Official

Immune reconstitution inflammatory syndrome [IRIS]

Excludes 2

Official

autoimmune disease (systemic) NOS (M35.9)Inherited from D50-D89, D89
certain conditions originating in the perinatal period (P00-P96)Inherited from D50-D89, D89
complications of pregnancy, childbirth and the puerperium (O00-O9A)Inherited from D50-D89, D89
congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)Inherited from D50-D89, D89
endocrine, nutritional and metabolic diseases (E00-E88)Inherited from D50-D89, D89
human immunodeficiency virus [HIV] disease (B20)Inherited from D50-D89, D89
injury, poisoning and certain other consequences of external causes (S00-T88)Inherited from D50-D89, D89
neoplasms (C00-D49)Inherited from D50-D89, D89
symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)Inherited from D50-D89, D89
transplant failure and rejection (T86.-)Inherited from D50-D89, D89

Related Codes

Official

D89.0Polyclonal hypergammaglobulinemia D89.1Cryoglobulinemia D89.2Hypergammaglobulinemia, unspecified D89.4Mast cell activation syndrome and related disorders D89.8Other specified disorders involving the immune mechanism, not elsewhere classified

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, D89
functional disorders of polymorphonuclear neutrophils (D71-)Inherited from D80-D89, D89
human immunodeficiency virus [HIV] disease (B20)Inherited from D80-D89, D89
hyperglobulinemia NOS (R77.1)Inherited from D80-D89, D89
monoclonal gammopathy (of undetermined significance) (D47.2)Inherited from D80-D89, D89

Code First

Official

No Code First sequencing instructions are included in this display for D89.3. Check the code and parent instructions in the Code Book.

Use Additional

Official

code for adverse effect, if applicable, to identify drug (T36-T50 with fifth or sixth character 5)

Code Also

Official

No Code Also instructions are included in this display for D89.3. Check the code and parent instructions in the Code Book.

Buddy Documentation Tip

HCC Buddy guidance

Documentation must clearly establish the diagnosis of immune reconstitution syndrome, the temporal relationship to immune recovery (initiation of antiretroviral therapy, discontinuation of immunosuppressive drugs, or post-transplant engraftment), and the specific infectious or inflammatory trigger.

The provider should document the patient's immune recovery markers (rising CD4 count, decreasing viral load) and the clinical manifestations requiring treatment.

MEAT Support

HCC Buddy guidance

The provider should document the patient's immune recovery markers (rising CD4 count, decreasing viral load) and the clinical manifestations requiring treatment.

Audit Caution

HCC Buddy guidance

Do not confuse immune reconstitution syndrome with treatment failure or new opportunistic infection

the paradoxical worsening is a hallmark feature. Ensure this code is not assigned for simple drug side effects or allergic reactions to antiretroviral therapy. Code the underlying HIV infection or immunocompromised state and the triggering infection separately in addition to this code.

Common Mistakes

HCC Buddy guidance

B20 (Human immunodeficiency virus disease) should be coded as the underlying condition when applicable but does not replace D89.

T86.- (Complications of transplanted organs and tissue) may be more appropriate if the clinical picture is graft rejection rather than immune reconstitution. D89.89 (Other specified disorders involving the immune mechanism) is a less specific alternative that should not be used when immune reconstitution syndrome is confirmed.

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 D89.3 an HCC code?

D89.3 is not in the CMS-HCC V28 or V24 community payment model. D89.3 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. D89.3 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: D89.3
Description: Immune reconstitution syndrome
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 D89.3 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT review for D89.3

For D89.3, 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

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What This Code Means

D89.3 is the ICD-10-CM diagnosis code for immune reconstitution syndrome. A syndrome that occurs when the immune system rapidly recovers after being suppressed, causing inflammation and tissue damage, often seen in HIV/AIDS patients starting antiretroviral therapy. D89.3 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).

D89.3 has no mapping under the CMS-HCC V28 or V24 community payment models. D89.3 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. D89.3 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.

This code is commonly used in immunocompromised patients, particularly those with HIV starting treatment.

HCC Buddy maintains structured V28 and V24 mapping, source-labeled coefficient references, and MEAT documentation criteria for D89.3 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•This code is commonly used in immunocompromised patients, particularly those with HIV starting treatment
•Document the specific manifestations and affected organs for complete clinical picture

Clinical Significance

Immune reconstitution inflammatory syndrome occurs when a recovering immune system mounts an excessive inflammatory response to previously acquired infections or antigens. It is most commonly seen in HIV patients initiating antiretroviral therapy but also occurs after discontinuation of immunosuppressive medications or following stem cell transplantation. The paradoxical worsening despite treatment improvement can be life-threatening, particularly with central nervous system involvement.

Documentation Requirements

✓Documentation must clearly establish the diagnosis of immune reconstitution syndrome, the temporal relationship to immune recovery (initiation of antiretroviral therapy, discontinuation of immunosuppressive drugs, or post-transplant engraftment), and the specific infectious or inflammatory trigger.
✓The provider should document the patient's immune recovery markers (rising CD4 count, decreasing viral load) and the clinical manifestations requiring treatment.

Use Additional Code

code for adverse effect, if applicable, to identify drug (T36-T50 with fifth or sixth character 5)

Commonly Confused Codes

•B20 (Human immunodeficiency virus disease) should be coded as the underlying condition when applicable but does not replace D89.
•T86.- (Complications of transplanted organs and tissue) may be more appropriate if the clinical picture is graft rejection rather than immune reconstitution. D89.89 (Other specified disorders involving the immune mechanism) is a less specific alternative that should not be used when immune reconstitution syndrome is confirmed.