D89.812 maps to CMS-HCC V28 454. A source-labeled RAF reference is available. Confirm the documented diagnosis and applicable coding requirements. MEAT criteria · RAF Calculator · HCC coding software

ICD-10-CM Code View

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Code lookupD89.812

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)

D89.812

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

Acute on chronic graft-versus-host disease

A condition where a patient with chronic graft-versus-host disease experiences a sudden worsening or new acute symptoms of immune attack on body tissues.

Buddy Insight

Overview Risk Models Code Book Documentation Audit Notes Edition comparison

CMS-HCC V28

Mapped

HCC 454

Stem Cell, Including Bone Mar...

Coefficient HCC 454: 1.068 (Community Non-Dual Aged (CNA))

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 251

HHS-HCC 251 adult, RAF varies...

Code-level coefficient reference

ESRD/PACE

Mapped

HCC 47

Disorders of Immunity

Code-level coefficient reference

RXHCC

Mapped

HCC 395

Stem Cell, Including Bone Mar...

Code-level coefficient reference

Code Book Path

Official

D89.8Other specified disorders involving the immune mechanism, not elsewhere classified D89.81Graft-versus-host disease D89.812Acute on chronic graft-versus-host disease

Inclusion Terms

Official

No inclusion terms are included in this display for D89.812. Check the code and parent instructions in the Code Book.

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

D89.810Acute graft-versus-host disease D89.811Chronic graft-versus-host disease D89.813Graft-versus-host disease, unspecified

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

underlying cause, such as:Inherited from D89.81
complications of transplanted organs and tissue (T86.-)Inherited from D89.81
complications of blood transfusion (T80.89)Inherited from D89.81

Use Additional

Official

code to identify associated manifestations, such as:Inherited from D89.81
desquamative dermatitis (L30.8)Inherited from D89.81
diarrhea (R19.7)Inherited from D89.81
elevated bilirubin (R17)Inherited from D89.81
hair loss (L65.9)Inherited from D89.81

Code Also

Official

No Code Also instructions are included in this display for D89.812. Check the code and parent instructions in the Code Book.

Buddy Documentation Tip

HCC Buddy guidance

Documentation must clearly identify both components: an existing chronic graft-versus-host disease diagnosis AND new or flaring acute features.

The provider should specify which organs demonstrate acute features versus chronic manifestations.

Treatment modifications including escalation of immunosuppression should be documented.

Prior transplant history and current immunosuppressive regimen are essential.

MEAT Support

HCC Buddy guidance

Documentation must clearly identify both components: an existing chronic graft-versus-host disease diagnosis AND new or flaring acute features.

The provider should specify which organs demonstrate acute features versus chronic manifestations.

Treatment modifications including escalation of immunosuppression should be documented.

Prior transplant history and current immunosuppressive regimen are essential.

Audit Caution

HCC Buddy guidance

This code specifically requires documented features of BOTH acute and chronic graft-versus-host disease concurrently.

Do not assign if a chronic graft-versus-host disease patient simply has worsening chronic features without true acute manifestations.

Ensure the overlap syndrome is explicitly documented by the treating physician rather than inferred from clinical findings.

Code transplant status (Z94.84) as well.

Common Mistakes

HCC Buddy guidance

D89.810 (Acute graft-versus-host disease) captures acute disease without pre-existing chronic disease. D89.811 (Chronic graft-versus-host disease) captures chronic disease without acute flare. D89.813 (Graft-versus-host disease, unspecified) loses important clinical specificity and should be avoided. Do not use both D89.810 and D89.811 simultaneously

D89.812 captures the overlap presentation.

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 D89.812 an HCC code?

Yes. D89.812 (Acute on chronic graft-versus-host disease) maps to HCC 454, Stem Cell, Including Bone Marrow, Transplant Status/Complications under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 1.068. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes. It is billable for payment year 2026.

Coder answer: D89.812 is billable and maps to V28 HCC 454, Stem Cell, Including Bone Marrow, Transplant Status/Complications. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code: D89.812
Description: Acute on chronic graft-versus-host disease
HCC (V28): HCC 454 — Stem Cell, Including Bone Marrow, Transplant Status/Complications
RAF reference coefficient: 1.068
Billable: Yes
Payment year: 2026

HCC Category Mapping

V28HCC 454, Stem Cell, Including Bone Marrow, Transplant Status/Complications

1.068

ESRDHCC 47, Disorders of Immunity

Not separately weighted

RxHCCHCC 395, Stem Cell, Including Bone Marrow, Transplant Status/Complications

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 D89.812 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT review for D89.812

For D89.812, 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

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What This Code Means

D89.812 is the ICD-10-CM diagnosis code for acute on chronic graft-versus-host disease. A condition where a patient with chronic graft-versus-host disease experiences a sudden worsening or new acute symptoms of immune attack on body tissues. D89.812 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, D89.812 maps to Stem Cell, Including Bone Marrow, Transplant Status/Complications (HCC 454) with a source-labeled community, non-dual, aged reference coefficient of 1.068. For CY2026 non-PACE Medicare Advantage, CMS uses 100% of the 2024 CMS-HCC model (V28). PACE uses a separate model blend. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes.

This code indicates both acute and chronic components are present simultaneously. For D89.812, 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. 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, source-labeled coefficient references, and MEAT documentation criteria for D89.812 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•This code indicates both acute and chronic components are present simultaneously
•Document the progression from chronic to acute phase and affected organs

Clinical Significance

Acute on chronic graft-versus-host disease represents an overlap syndrome where patients with established chronic graft-versus-host disease develop new acute features (classic acute skin rash, hepatitis, or enteritis). This presentation indicates disease instability requiring escalation of immunosuppressive therapy and carries a worse prognosis than either form alone. It reflects the complex immunologic dysregulation inherent in post-transplant patients.

Documentation Requirements

✓Documentation must clearly identify both components: an existing chronic graft-versus-host disease diagnosis AND new or flaring acute features.
✓The provider should specify which organs demonstrate acute features versus chronic manifestations.
✓Treatment modifications including escalation of immunosuppression should be documented.
✓Prior transplant history and current immunosuppressive regimen are essential.

Commonly Confused Codes

•D89.810 (Acute graft-versus-host disease) captures acute disease without pre-existing chronic disease. D89.811 (Chronic graft-versus-host disease) captures chronic disease without acute flare. D89.813 (Graft-versus-host disease, unspecified) loses important clinical specificity and should be avoided. Do not use both D89.810 and D89.811 simultaneously
•D89.812 captures the overlap presentation.