D46.1 ICD-10-CM Code: Refractory anemia with ring sideroblasts
D46.1 maps to CMS-HCC V28 19. A source-labeled RAF reference is available. Confirm the documented diagnosis and applicable coding requirements. MEAT criteria · RAF Calculator · free HCC coding tools
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FY 2026 Apr update / Neoplasms (C00-D49) / Neoplasms of uncertain behavior, polycythemia vera and myelodysplastic syndromes (D37-D48)
D46.1
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceRefractory anemia with ring sideroblasts
A bone marrow disorder where red blood cells cannot be produced normally and ring sideroblasts (abnormal iron-containing cells) are present in the bone marrow.
Buddy Insight
Refractory anemia with ring sideroblasts is a myelodysplastic syndrome subtype characterized by iron-laden mitochondria forming a ring pattern around the nucleus of erythroblasts in the bone marrow.
CMS-HCC V28
MappedHCC 19
Coefficient HCC 19: 1.798 (Community Non-Dual Aged (CNA))
CMS-HCC V24
HistoricalHistorical
Not used for CY2026 payment
ACA/HHS
MappedHCC 067
Code-level coefficient reference
ESRD/PACE
MappedHCC 46
Code-level coefficient reference
RXHCC
MappedHCC 19
Code-level coefficient reference
Code Book Path
Inclusion Terms
Official- RARS
Excludes 2
Official- drug-induced aplastic anemia (D61.1)Inherited from D46
Related Codes
Includes
OfficialNo Includes notes are included in this display for D46.1. Check the code and parent instructions in the Code Book.
Excludes 1
Official- neoplasms of unspecified behavior (D49.-)Inherited from D37-D48
Code First
OfficialNo Code First sequencing instructions are included in this display for D46.1. Check the code and parent instructions in the Code Book.
Use Additional
Official- code for adverse effect, if applicable, to identify drug (T36-T50 with fifth or sixth character 5)Inherited from D46
Code Also
OfficialNo Code Also instructions are included in this display for D46.1. Check the code and parent instructions in the Code Book.
Buddy Documentation Tip
MEAT Support
Audit Caution
Common Mistakes
Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →
Is D46.1 an HCC code?
Yes. D46.1 (Refractory anemia with ring sideroblasts) maps to HCC 19, Myelodysplastic Syndromes, Multiple Myeloma, and Other Cancers under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 1.798. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes. It is billable for payment year 2026.
Coder answer: D46.1 is billable and maps to V28 HCC 19, Myelodysplastic Syndromes, Multiple Myeloma, and Other Cancers. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.
- Code
- D46.1
- Description
- Refractory anemia with ring sideroblasts
- HCC (V28)
- HCC 19 — Myelodysplastic Syndromes, Multiple Myeloma, and Other Cancers
- RAF reference coefficient
- 1.798
- Billable
- Yes
- Payment year
- 2026
HCC Category Mapping
These are source-labeled model coefficients, not member totals. A category may still be removed by hierarchy or model cleanup rules. Weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. Actual per-patient RAF contribution depends on member context, hierarchy and cleanup rules, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains available for historical review.
Work D46.1 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →
MEAT review for D46.1
For D46.1, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.
- 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
Coder workflow notes
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What This Code Means
D46.1 is the ICD-10-CM diagnosis code for refractory anemia with ring sideroblasts. A bone marrow disorder where red blood cells cannot be produced normally and ring sideroblasts (abnormal iron-containing cells) are present in the bone marrow. D46.1 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, D46.1 maps to Myelodysplastic Syndromes, Multiple Myeloma, and Other Cancers (HCC 19) with a source-labeled community, non-dual, aged reference coefficient of 1.798. For CY2026 non-PACE Medicare Advantage, CMS uses 100% of the 2024 CMS-HCC model (V28). PACE uses a separate model blend. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes.
Ring sideroblasts must be documented and confirmed on bone marrow examination. For D46.1, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule. 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, source-labeled coefficient references, and MEAT documentation criteria for D46.1 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Ring sideroblasts must be documented and confirmed on bone marrow examination
- •This subtype has a different prognosis than D46.0, so accurate differentiation is important
Clinical Significance
Refractory anemia with ring sideroblasts is a myelodysplastic syndrome subtype characterized by iron-laden mitochondria forming a ring pattern around the nucleus of erythroblasts in the bone marrow. This subtype generally has a more favorable prognosis than other myelodysplastic syndromes, with lower risk of transformation to acute myeloid leukemia.
Documentation Requirements
- ✓Documentation must include bone marrow biopsy confirming ring sideroblasts (at least 15% of erythroblasts) with Prussian blue staining.
- ✓The blast percentage must be below 5%.
- ✓Document iron studies, cytogenetic analysis, and the SF3B1 mutation status if tested, as this mutation is found in most cases and is associated with better outcomes.
Commonly Confused Codes
- •D46.0 (refractory anemia without ring sideroblasts) lacks the ring sideroblast finding.
- •D46.B (refractory cytopenia with multilineage dysplasia and ring sideroblasts) indicates dysplasia in multiple cell lines.
- •D64.0 (hereditary sideroblastic anemia) is a congenital condition distinct from myelodysplastic syndrome.
- •D64.3 (other sideroblastic anemias) is used for acquired non-myelodysplastic forms.