D64.1
BillableSecondary sideroblastic anemia due to disease
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is D64.1 an HCC code?
Yes. D64.1 maps to Acquired Hemolytic, Aplastic, and Sideroblastic Anemias under the CMS-HCC V28 risk adjustment model (and Coagulation Defects and Other Specified 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 D64.1
For D64.1to 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 D64.1 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
D64.1 is the ICD-10-CM diagnosis code for secondary sideroblastic anemia due to disease. A condition where the body cannot properly use iron to make hemoglobin due to an underlying disease or condition rather than genetic causes. D64.1 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 aplastic and other anemias and other bone marrow failure syndromes (d60-d64).
Under the CMS-HCC V28 risk adjustment model, D64.1 maps to Acquired Hemolytic, Aplastic, and Sideroblastic Anemias (HCC 109) with a community, non-dual, aged base RAF weight of 1.144. Under the older CMS-HCC V24 model, D64.1 maps to Coagulation Defects and Other Specified Hematological Disorders (HCC 48) with a community, non-dual, aged base RAF weight of 0.192. 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.
Always code the underlying disease causing the sideroblastic anemia as the primary condition. Because D64.1 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 D64.1 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Always code the underlying disease causing the sideroblastic anemia as the primary condition
- •Common causes include malignancy, infections, medications, and metabolic disorders
Clinical Significance
Secondary sideroblastic anemia due to disease occurs when an underlying medical condition impairs mitochondrial heme synthesis, producing abnormal ring sideroblasts in the bone marrow. Common causative conditions include rheumatoid arthritis, connective tissue disorders, myeloproliferative and lymphoproliferative disorders, hypothyroidism, and chronic inflammatory states. The sideroblastic component often resolves when the underlying disease is adequately treated, distinguishing it from hereditary and drug-induced forms.
Documentation Requirements
- ✓Document the underlying disease causing the secondary sideroblastic anemia.
- ✓Record bone marrow biopsy findings showing ring sideroblasts.
- ✓Include hemoglobin level, mean corpuscular volume, serum iron studies, and ferritin level.
- ✓Document the temporal relationship between the underlying disease and sideroblastic anemia onset.
- ✓Code the underlying condition as the primary diagnosis.
- ✓Note any treatment response when the underlying condition is addressed.
Code First
- underlying disease
Commonly Confused Codes
- •D64.0 (Hereditary sideroblastic anemia) is for inherited forms with genetic mutations.
- •D64.2 (Secondary sideroblastic anemia due to drugs and toxins) is for medication or toxin-related causes.
- •D46.1 (Refractory anemia with ring sideroblasts) is an acquired myelodysplastic syndrome.
- •D64.3 (Other sideroblastic anemias) is a less specific category.
- •D64.9 (Anemia, unspecified) does not capture the sideroblastic mechanism.