D89.812
BillableAcute on chronic graft-versus-host disease
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is D89.812 an HCC code?
Yes. D89.812 maps to Graft-Versus-Host Disease and Stem Cell Transplant Complications under the CMS-HCC V28 risk adjustment model (and Disorders of Immunity under V24).
HCC Category Mapping
RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. 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.
MEAT Criteria for D89.812
For D89.812 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 D89.812 during that encounter — not just copy-forwarded from a problem list.
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 Graft-Versus-Host Disease and Stem Cell Transplant Complications (HCC 454) with a community, non-dual, aged base RAF weight of 0.000. Under the older CMS-HCC V24 model, D89.812 maps to Disorders of Immunity (HCC 47) with a community, non-dual, aged base RAF weight of 0.472. 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 code indicates both acute and chronic components are present simultaneously. Because D89.812 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 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.