2026 ICD-10-CM Diagnosis Code D46.CMyelodysplastic syndrome with isolated del(5q) chromosomal abnormality
ICD-10-CM Codes›C00–D49›D37-D48›D46
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- Risk Adjusts — HCC 19
- Not Chronic
D46.C is a billable ICD-10-CM diagnosis code for myelodysplastic syndrome with isolated del(5q) chromosomal abnormality. 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. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 133 closely related codes. Coders also document this condition as myelodysplastic syndrome with isolated del. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Myelodysplastic syndrome (MDS).
For Medicare Advantage risk adjustment, D46.C maps to CMS-HCC Category 19 (Myelodysplastic Syndromes, Multiple Myeloma, and Other Cancers) under the V28 model, adding a risk factor of about 1.798 for a community, non-dual, aged beneficiary in payment year 2026.
Code Identity
Code Classification
Medicare Risk Adjustment (HCC)Billing
D46.C 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.
- Myelodysplastic syndrome with isolated del
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Inclusion Terms
- Myelodysplastic syndrome with 5q deletion
- 5q minus syndrome NOS
These terms are the conditions for which that code is to be used. The terms may be synonyms of the code title, or, in the case of "other specified" codes, the terms are a list of the various conditions assigned to that code. The inclusion terms are not necessarily exhaustive. Additional terms found only in the Alphabetic Index may also be assigned to a code.
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
Myelodysplastic syndrome See Also: Syndrome, myelodysplastic; D46.9
5q deletion D46.C
Syndrome See Also: Disease;
5q minus NOS D46.C
5q deletion D46.C
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Myelodysplastic Syndromes
clonal hematopoietic stem cell disorders characterized by dysplasia in one or more hematopoietic cell lineages. they predominantly affect patients over 60, are considered preleukemic conditions, and have high probability of transformation into acute myeloid leukemia.
Patient EducationClinical
Myelodysplastic Syndromes
Your bone marrow is the spongy tissue inside some of your bones, such as your hip and thigh bones. It contains immature cells, called stem cells. The stem cells can develop into the red blood cells that carry oxygen through your body, the white blood cells that fight infections, and the platelets that help with blood clotting.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert D46.C to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About D46.COverview
What is the ICD-10 code for myelodysplastic syndrome with isolated del(5q) chromosomal abnormality?
The ICD-10-CM code for myelodysplastic syndrome with isolated del(5q) chromosomal abnormality is D46.C (sometimes written as D46C). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
Is D46.C (Myelodysplastic syndromes) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report myelodysplastic syndrome with isolated del(5q) chromosomal abnormality on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does D46.C group to?
When myelodysplastic syndrome with isolated del(5q) chromosomal abnormality is the principal diagnosis on an inpatient stay, it groups to MS-DRG 811, 812, with relative weights from 0.9182 to 1.4043 depending on complications. Higher weights mean higher Medicare reimbursement.
Is D46.C a CC or MCC?
CMS lists D46.C as a CC (complication or comorbidity) for FY 2026. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 133 closely related codes in its exclusion list.
What is the ICD-9 equivalent of D46.C?
Under the General Equivalence Mappings, myelodysplastic syndrome with isolated del(5q) chromosomal abnormality converts to ICD-9-CM 238.74 (myelodyspls syn w 5q del). The mapping is a direct match.
What HCC is D46.C?
D46.C (myelodysplastic syndrome with isolated del(5q) chromosomal abnormality) maps to CMS-HCC Category 19 (Myelodysplastic Syndromes, Multiple Myeloma, and Other Cancers), commonly written as HCC 19, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2026. It mapped to HCC 46 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 16.
Does D46.C risk-adjust for Medicare Advantage payment?
Yes. When documented and reported on a Medicare Advantage encounter, D46.C adds a risk adjustment factor of about 1.798 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.957 to 1.989 depending on the payment segment). A more severe related category (HCC 17 and HCC 18) supersedes it when both are reported. See the full factor table on the HCC 19 category page.
