D59.32
BillableHereditary hemolytic-uremic syndrome
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is D59.32 an HCC code?
Yes. D59.32 maps to Hemolytic and Aplastic Anemias under the CMS-HCC V28 risk adjustment model (and Severe Hematological Disorders 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 D59.32
For D59.32 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 D59.32 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
D59.32 is the ICD-10-CM diagnosis code for hereditary hemolytic-uremic syndrome. A rare inherited genetic disorder that causes recurrent episodes of red blood cell destruction and kidney damage. D59.32 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 hemolytic anemias (d55-d59).
Under the CMS-HCC V28 risk adjustment model, D59.32 maps to Hemolytic and Aplastic Anemias (HCC 109) with a community, non-dual, aged base RAF weight of 0.291. Under the older CMS-HCC V24 model, D59.32 maps to Severe Hematological Disorders (HCC 46) with a community, non-dual, aged base RAF weight of 0.666. 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.
Confirm family history documentation to support the hereditary nature of the condition. Because D59.32 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 D59.32 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Confirm family history documentation to support the hereditary nature of the condition
- •Note any genetic testing results or family members affected by the same condition
Clinical Significance
Hereditary hemolytic-uremic syndrome (atypical hemolytic-uremic syndrome) is a rare genetic disorder caused by mutations in complement regulatory proteins (factor H, factor I, membrane cofactor protein, C3, factor B, or thrombomodulin) leading to uncontrolled complement activation on endothelial surfaces. Unlike the more common infection-associated form, hereditary hemolytic-uremic syndrome has a high recurrence rate, progresses to end-stage renal disease in up to 50% of cases, and requires chronic complement inhibitor therapy (eculizumab or ravulizumab) to prevent relapses.
Documentation Requirements
- ✓Document genetic testing results identifying the specific complement pathway mutation when available.
- ✓Record complement levels (C3, C4, factor H, factor I) and functional assays.
- ✓Include family history of hemolytic-uremic syndrome or unexplained renal failure.
- ✓Document the triad findings (microangiopathic hemolytic anemia, thrombocytopenia, acute kidney injury) with supporting laboratory values.
- ✓Record treatment with complement inhibitors, plasma exchange history, and renal function trajectory including any transplant considerations.