2027 ICD-10-CM Diagnosis Code C94.6Myelodysplastic disease, not elsewhere classified
ICD-10-CM Codes›C00–D49›C81-C96›C94
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- Risk Adjusts — HCC 19
- Chronic Condition
C94.6 is a billable ICD-10-CM diagnosis code for myelodysplastic disease, not elsewhere classified. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 820 through 825, 840 through 842. 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/myeloproliferative disease. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Leukemia - all other types.
For Medicare Advantage risk adjustment, C94.6 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 2027.
Code Identity
Code Classification
Medicare Risk Adjustment (HCC)Billing
C94.6 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 2027.
Source: CMS Payment Year 2027 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/myeloproliferative disease
- Myelodysplastic/myeloproliferative neoplasm, unclassifiable
- Pulmonary hypertension due to hematological disorder
- Pulmonary hypertension due to myeloproliferative disorder
- Vasculitis due to myeloproliferative disorder
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to C94.6: its own notes plus those printed at C94, block C81-C96, and Chapter 2. A note printed at a category, block or chapter applies to every code under it.
Applicable To
Conditions this code is used for: synonyms of the title or, for "other specified" codes, the conditions assigned to it. The list is not exhaustive.
- Myelodysplastic/myeloproliferative neoplasm, unclassifiable
- Myeloproliferative disease, not elsewhere classified
Excludes1
Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.
Excludes2
Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.
Notes
General instructions on how these codes are used.
- Functional activity
- All neoplasms are classified in this chapter, whether they are functionally active or not. An additional code from Chapter 4 may be used, to identify functional activity associated with any neoplasm.
- Morphology [Histology]
- Chapter 2 classifies neoplasms primarily by site (topography), with broad groupings for behavior, malignant, in situ, benign, etc. The Table of Neoplasms should be used to identify the correct topography code. In a few cases, such as for malignant melanoma and certain neuroendocrine tumors, the morphology (histologic type) is included in the category and codes.
- Primary malignant neoplasms overlapping site boundaries
- A primary malignant neoplasm that overlaps two or more contiguous (next to each other) sites should be classified to the subcategory/code .8 ('overlapping lesion'), unless the combination is specifically indexed elsewhere. For multiple neoplasms of the same site that are not contiguous, such as tumors in different quadrants of the same breast, codes for each site should be assigned.
- Malignant neoplasm of ectopic tissue
- Malignant neoplasms of ectopic tissue are to be coded to the site mentioned, e.g., ectopic pancreatic malignant neoplasms are coded to pancreas, unspecified (C25.9).
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name C94.6, its category, or a range that includes it.
Applicable To 2
These notes mention C94.6.
Excludes1 4
These codes carry an Excludes1 note naming C94.6: they are not reported together with it, unless the two conditions are unrelated.
Code First 3
These codes say to code first a condition named in the note, and C94.6 is one of the conditions named.
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
Disease, diseased See Also: Syndrome;
myelodysplastic See Also: Syndrome, myelodysplastic; C94.6
myelodysplastic/myeloproliferative neoplasm, unclassifiable C94.6
not classified C94.6
specified NEC C94.6
unclassifiable C94.6
Neoplasm, neoplastic See Also: Table of Neoplasms;
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
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 C94.6 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About C94.6Overview
What is the ICD-10 code for myelodysplastic disease, not elsewhere classified?
The ICD-10-CM code for myelodysplastic disease, not elsewhere classified is C94.6 (sometimes written as C946). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is C94.6 (Other leukemias of specified cell type) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report myelodysplastic disease, not elsewhere classified on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does C94.6 group to?
When myelodysplastic disease, not elsewhere classified is the principal diagnosis on an inpatient stay, it groups to MS-DRG 841, 821, 822, 825, 842, 824, 840, 820, 823, with relative weights from 0.9948 to 6.2454 depending on complications. Higher weights mean higher Medicare reimbursement.
Is C94.6 a CC or MCC?
CMS lists C94.6 as a CC (complication or comorbidity) for FY 2027. 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.
Can C94.6 be reported with a code from C91.4?
Not as a rule. The Excludes1 note at C94, which applies to C94.6, lists "leukemic reticuloendotheliosis (C91.4-)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).
What HCC is C94.6?
C94.6 (myelodysplastic disease, not elsewhere classified) 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 2027. 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 21.
Does C94.6 risk-adjust for Medicare Advantage payment?
Yes. When documented and reported on a Medicare Advantage encounter, C94.6 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.
