2026 CMS-HCC Risk Adjustment Categories ICD-10-CM
Hierarchical Condition Categories (HCCs) are the condition groups CMS uses to risk-adjust Medicare Advantage payments. Diagnosis codes documented during the year map to HCCs, and each payment HCC adds a published weight to the beneficiary's risk adjustment factor (RAF), which sets the plan's monthly payment. For payment year 2026 the CMS-HCC V28 model pays 100% of Medicare Advantage risk scores: 8,019 ICD-10-CM codes map to one of its 115 payment categories. Every mapped code page on ICD List shows its category and RAF weight.
All 115 CMS-HCC V28 Categories 8,019 codes mapped
RAF weight shown is the community, non-dual, aged factor for payment year 2026; each category page lists all seven payment segments with its full code list and hierarchy.
HCC Coding Basics
What does HCC mean in a diagnosis?
HCC stands for Hierarchical Condition Category. When a diagnosis is described as "an HCC," it means the ICD-10-CM code documented for that condition maps to one of the 115 payment categories in the CMS-HCC model, so it affects the patient's Medicare risk score. The diagnosis itself does not change; the HCC label describes its role in payment, not in clinical care.
What is HCC coding used for, and why does it matter?
CMS pays Medicare Advantage plans a fixed monthly amount per enrollee, adjusted for health status. Without that adjustment, plans would profit by enrolling only healthy beneficiaries and avoiding sick ones. Risk adjustment removes that incentive: diagnoses documented during the year map to HCCs, each HCC carries a published weight, and the resulting risk score raises or lowers the plan's payment so that caring for sicker patients is paid accurately. That is why complete, specific diagnosis coding matters financially as well as clinically: an undocumented chronic condition is an HCC that never reaches the risk score.
Source: CMS, Report to Congress: Risk Adjustment in Medicare Advantage (December 2024), Section 2.1.
An HCC coding example: how a RAF score adds up
A 74-year-old man living in the community (non-dual, aged) is treated during the year for type 2 diabetes with circulatory complications (E11.59) and heart failure (I50.9). His risk adjustment factor for payment year 2026 builds like this:
A RAF of 1.0 represents the average Medicare beneficiary, so this enrollee's plan is paid about 3.4% above the base rate. Every weight above is the published PY 2026 V28 community factor; each code page on ICD List shows the same numbers for that specific diagnosis.
How the hierarchy works
The "hierarchical" part means related categories suppress each other so a condition is never paid twice. A patient coded for both an acute myocardial infarction (HCC 228) and unstable angina (HCC 229) is paid only for the AMI, because it is the more severe manifestation of the same coronary artery disease. Unrelated categories, like the diabetes and heart failure examples above, all count.
Is HCC coding inpatient or outpatient?
Both. Risk adjustment accepts diagnoses from hospital inpatient stays, hospital outpatient visits, and face-to-face professional encounters alike; what matters is that the condition is documented, supported by the record, and reported at least once during the calendar year. HCC coding is therefore different from MS-DRG grouping, which applies only to inpatient claims.
What do V24 and V28 mean?
They are versions of the CMS-HCC model. V24 (86 categories, calibrated on older data) was retired for Medicare Advantage payment; V28 (115 categories, recalibrated and renumbered) phased in from 2024 and pays 100% of the MA risk score from payment year 2026. V24 still appears in lookback work and RADV audits, which is why ICD List keeps a V24 archive alongside the live V28 pages.
Model Transition Guides
V24 to V28: What Changed
The restructuring in one place: every diagnosis code dropped from risk adjustment, every code added, and the renumbering that moved most categories.
Built from both CMS mapping vintages→Editorial GuideCodes That No Longer Risk-Adjust
Diagnoses that mapped to a payment HCC under V24 but map to none under V28, the most common lookback question of the transition.
Grouped by chapter, filterable→ArchiveCMS-HCC V24 Archive
The retired 86-category model kept browsable for lookback analysis and RADV audit periods that predate the transition.
With live V28 successor links→Questions About CMS-HCC Risk Adjustment
What is a CMS-HCC category?
A Hierarchical Condition Category groups clinically related, cost-predictive diagnosis codes. CMS assigns each payment HCC a relative factor; the sum of a beneficiary's demographic factors and HCC factors is their RAF score, which scales the Medicare Advantage plan's capitated payment.
How many ICD-10-CM codes map to an HCC in 2026?
8,019 ICD-10-CM diagnosis codes map to one of the 115 payment categories in the CMS-HCC V28 model for payment year 2026, out of more than 74,000 billable codes. Every ICD List code page states whether the code risk-adjusts and at what weight.
What changed between V24 and V28?
V28 restructured the model from 86 to 115 payment categories, renumbered most of them, removed thousands of diagnosis codes from risk adjustment, and added others. Payment phased in over 2024 and 2025; from payment year 2026, V28 determines 100% of the MA risk score. The complete lists are on V24 to V28: What Changed.
Is CMS-HCC V24 still used for anything?
Not for Medicare Advantage payment. V24 remains relevant for lookback analysis, RADV audit periods that predate the transition, and PACE organizations still paid on the related V22 model. The V24 archive keeps its 86 categories and mappings available.
Does HCC coding apply to inpatient or outpatient claims?
Both. Diagnoses from hospital inpatient, hospital outpatient, and professional face-to-face encounters all feed risk adjustment, as long as they are documented and reported during the calendar year. Site of service changes nothing about the HCC weight.
Where can I find the list of HCC codes for 2026?
The table above lists all 115 categories, and each category page carries its complete ICD-10-CM code list with RAF weights for payment year 2026. The underlying CMS mapping file is linked in the official sources below.
Official Sources & Methodology
Every mapping, label, and weight on the HCC pages is loaded verbatim from the published CMS files, with no interpretation added, and refreshed with each CMS release.
- CMS Risk Adjustment ICD-10-CM MappingsThe category tables and every code-to-HCC mapping on ICD List come from the published mapping files.
- CMS-HCC Model SoftwareSource of all RAF weights, category labels, and hierarchy rules, including the PACE, ESRD, and RxHCC models.
- Report to Congress: Risk Adjustment in Medicare Advantage (December 2024)Basis for the explanatory copy on this page, including the function of risk adjustment and the clinical vignette pattern.
ICD List is not affiliated with CMS. This page is a coding and payment reference, not medical or actuarial advice.
Related References
Source: Centers for Medicare & Medicaid Services, Payment Year 2026 risk adjustment mapping and model software releases (CMS-HCC V28), applied to the FY 2026 ICD-10-CM code set.
