D46.B
BillableRefractory cytopenia with multilineage dysplasia and ring sideroblasts
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is D46.B an HCC code?
Yes. D46.B maps to Lymphoma and Other Cancers 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 D46.B
For D46.Bto 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 D46.B during that encounter — not just copy-forwarded from a problem list.
What This Code Means
D46.B is the ICD-10-CM diagnosis code for refractory cytopenia with multilineage dysplasia and ring sideroblasts. A bone marrow disorder where blood cells develop abnormally with multiple cell lines affected and iron-laden cells present, making it difficult to treat. D46.B sits in the ICD-10-CM chapter for neoplasms (c00-d49), within the section covering neoplasms of uncertain behavior, polycythemia vera and myelodysplastic syndromes (d37-d48).
Under the CMS-HCC V28 risk adjustment model, D46.B maps to Lymphoma and Other Cancers (HCC 19) with a community, non-dual, aged base RAF weight of 0.105. Under the older CMS-HCC V24 model, D46.B 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.
This is a specific subtype of myelodysplastic syndrome; ensure cytopathology or bone marrow biopsy documentation supports the diagnosis. Because D46.B 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 D46.B sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •This is a specific subtype of myelodysplastic syndrome; ensure cytopathology or bone marrow biopsy documentation supports the diagnosis
- •Verify ring sideroblasts are present (≥15%) and multilineage dysplasia is confirmed before coding this specific subtype
Clinical Significance
Refractory cytopenia with multilineage dysplasia and ring sideroblasts combines the features of multilineage bone marrow dysplasia with abnormal iron-laden erythroid precursors. This subtype reflects a complex bone marrow failure state but may carry a relatively favorable prognosis compared to excess blast subtypes, particularly when the SF3B1 mutation is present.
Documentation Requirements
- ✓Documentation must include bone marrow biopsy confirming multilineage dysplasia (at least two cell lines affected), ring sideroblasts at 15% or greater on Prussian blue staining, and blast percentage below 5%.
- ✓Cytogenetic analysis and SF3B1 mutation status should be documented.
- ✓Iron studies and transfusion requirements should be recorded.
Commonly Confused Codes
- •D46.A (refractory cytopenia with multilineage dysplasia without ring sideroblasts) lacks the ring sideroblast component.
- •D46.1 (refractory anemia with ring sideroblasts) has single-lineage dysplasia only.
- •D64.3 (other sideroblastic anemias) covers acquired non-myelodysplastic forms.
- •D46.20-D46.22 (excess blasts) have higher blast counts.