2026 ICD-10-CM Diagnosis Code B33.24Viral cardiomyopathy
B33.24 is a billable ICD-10-CM diagnosis code for viral cardiomyopathy. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 314 through 316. Coders also document this condition as cardiomyopathy due to viral infection. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Myocarditis and cardiomyopathy and Viral infection.
For Medicare Advantage risk adjustment, B33.24 maps to CMS-HCC Category 227 (Cardiomyopathy/Myocarditis) under the V28 model, adding a risk factor of about 0.189 for a community, non-dual, aged beneficiary in payment year 2026.
Code Identity
Code Classification
Medicare Risk Adjustment (HCC)Billing
B33.24 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.
- Cardiomyopathy due to viral infection
- Cardiovascular abnormality due to infective myocarditis
- Dilated cardiomyopathy due to infectious disease
- Dilated cardiomyopathy due to viral myocarditis
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
Cardiomyopathy
Cardiomyopathy is the name for diseases of the heart muscle. These diseases enlarge your heart muscle or make it thicker and more rigid than normal. In rare cases, scar tissue replaces the muscle tissue.
Read the full article at MedlinePlus
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Convert B33.24 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About B33.24Overview
What is the ICD-10 code for viral cardiomyopathy?
The ICD-10-CM code for viral cardiomyopathy is B33.24 (sometimes written as B3324). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
Is B33.24 (Viral carditis) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report viral cardiomyopathy on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does B33.24 group to?
When viral cardiomyopathy is the principal diagnosis on an inpatient stay, it groups to MS-DRG 314, 315, 316, with relative weights from 0.6821 to 2.0852 depending on complications. Higher weights mean higher Medicare reimbursement.
What is the ICD-9 equivalent of B33.24?
Under the General Equivalence Mappings, viral cardiomyopathy converts to ICD-9-CM 078.89 (oth spec dis viruses). The mapping is approximate, so confirm the match fits the documentation.
What HCC is B33.24?
B33.24 (viral cardiomyopathy) maps to CMS-HCC Category 227 (Cardiomyopathy/Myocarditis), commonly written as HCC 227, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2026. It mapped to HCC 85 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 186.
Does B33.24 risk-adjust for Medicare Advantage payment?
Yes. When documented and reported on a Medicare Advantage encounter, B33.24 adds a risk adjustment factor of about 0.189 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.145 to 0.200 depending on the payment segment). A more severe related category (HCC 221, HCC 222, HCC 223, HCC 224, HCC 225, and HCC 226) supersedes it when both are reported. See the full factor table on the HCC 227 category page.
