D59.4
BillableOther nonautoimmune hemolytic anemias
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is D59.4 an HCC code?
Yes. D59.4 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 D59.4
For D59.4 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 D59.4 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
D59.4 is the ICD-10-CM diagnosis code for other nonautoimmune hemolytic anemias. Anemia caused by the destruction of red blood cells through mechanisms that do not involve the immune system or drugs. D59.4 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, D59.4 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, D59.4 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.
Ensure the hemolytic anemia is not autoimmune (D59.0-D59.1) or drug-induced (D59.2) before assigning this code. Because D59.4 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 D59.4 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
Clinical Significance
Other nonautoimmune hemolytic anemias encompasses acquired hemolytic anemias caused by non-immune mechanisms other than drugs, including mechanical hemolysis from prosthetic heart valves (march hemoglobinuria), microangiopathic hemolytic anemia from disseminated intravascular coagulation or malignant hypertension, thermal injury to red blood cells, and hemolysis from hypotonic solutions or osmotic stress. The direct antiglobulin (Coombs) test is negative, distinguishing these from autoimmune causes. Treatment targets the underlying mechanical, thermal, or chemical cause.
Documentation Requirements
- ✓Document the specific mechanism of hemolysis (mechanical, thermal, chemical, osmotic).
- ✓Record the negative direct antiglobulin test excluding autoimmune etiology.
- ✓Include hemoglobin values, peripheral blood smear findings (schistocytes for mechanical hemolysis), and hemolysis markers.
- ✓Document the underlying cause such as prosthetic valve dysfunction, disseminated intravascular coagulation, or other triggering condition.
- ✓Record treatment directed at the underlying cause.
Commonly Confused Codes
- •D59.0 (Drug-induced autoimmune hemolytic anemia) and D59.2 (Drug-induced nonautoimmune hemolytic anemia) are used when drugs are the cause.
- •D59.10-D59.19 (Autoimmune hemolytic anemias) have positive Coombs tests.
- •D59.30-D59.39 (Hemolytic-uremic syndrome) are specific thrombotic microangiopathy codes.
- •D65 (Disseminated intravascular coagulation) should be coded separately when it is the cause of microangiopathic hemolysis.