2026 ICD-10-CM Diagnosis Code D64.1Secondary sideroblastic anemia due to disease
D64.1 is a billable ICD-10-CM diagnosis code for secondary sideroblastic anemia due to disease. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 811 through 812. The code is a manifestation code that cannot be reported as the principal diagnosis. Coders also document this condition as secondary acquired sideroblastic anemia. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Aplastic anemia.
For Medicare Advantage risk adjustment, D64.1 maps to CMS-HCC Category 109 (Acquired Hemolytic, Aplastic, and Sideroblastic Anemias) under the V28 model, adding a risk factor of about 1.144 for a community, non-dual, aged beneficiary in payment year 2026.
Code Identity
Code Classification
Code EditsBilling
Medicare Code Editor checks that affect claim validity for D64.1.
Medicare Risk Adjustment (HCC)Billing
D64.1 maps to a payment category in the CMS-HCC model used to risk-adjust Medicare Advantage payments. Weights are the published community factors for payment year 2026.
Source: CMS Payment Year 2026 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Secondary acquired sideroblastic anemia
- Secondary sideroblastic anemia due to disease
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Code First
- underlying disease
Certain conditions have both an underlying etiology and multiple body system manifestations due to the underlying etiology. For such conditions, the ICD-10-CM has a coding convention that requires the underlying condition be sequenced first followed by the manifestation. Wherever such a combination exists, there is a "use additional code" note at the etiology code, and a "code first" note at the manifestation code. These instructional notes indicate the proper sequencing order of the codes, etiology followed by manifestation.
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Anemia
If you have anemia, your blood does not carry enough oxygen to the rest of your body. The most common cause of anemia is not having enough iron. Your body needs iron to make hemoglobin. Hemoglobin is an iron-rich protein that gives the red color to blood. It carries oxygen from the lungs to the rest of the body.
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Convert D64.1 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About D64.1Overview
What is the ICD-10 code for secondary sideroblastic anemia due to disease?
The ICD-10-CM code for secondary sideroblastic anemia due to disease is D64.1 (sometimes written as D641). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
Is D64.1 (Other anemias) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report secondary sideroblastic anemia due to disease on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does D64.1 group to?
On inpatient claims, secondary sideroblastic anemia due to disease maps to MS-DRG 811, 812, with relative weights from 0.9182 to 1.4043 depending on complications. Higher weights mean higher Medicare reimbursement.
Can D64.1 be a principal diagnosis?
No. This is a manifestation code: secondary sideroblastic anemia due to disease describes the manifestation of an underlying disease rather than the disease itself, so the underlying condition is sequenced first.
What is the ICD-9 equivalent of D64.1?
Under the General Equivalence Mappings, secondary sideroblastic anemia due to disease converts to ICD-9-CM 285.0 (sideroblastic anemia). The mapping is approximate, so confirm the match fits the documentation.
What HCC is D64.1?
D64.1 (secondary sideroblastic anemia due to disease) maps to CMS-HCC Category 109 (Acquired Hemolytic, Aplastic, and Sideroblastic Anemias), commonly written as HCC 109, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2026. It mapped to HCC 48 under the retired V24 model. It also maps in the PACE (CMS-HCC V22), ESRD (V21), and ESRD (V24) models. In the Part D prescription drug model it maps to RxHCC 96.
Does D64.1 risk-adjust for Medicare Advantage payment?
Yes. When documented and reported on a Medicare Advantage encounter, D64.1 adds a risk adjustment factor of about 1.144 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.529 to 1.815 depending on the payment segment). HCC 109 sits at the top of its hierarchy, so no other condition category supersedes it. See the full factor table on the HCC 109 category page.
