Centers for Medicare & Medicaid Services (CMS) just added 487 new ICD-10-CM codes.
That’s 487 new ways your Medicare Advantage plan could face an audit setback.
One coding error could cost millions. Will your team catch it?
During your Monday risk adjustment review, you spot it: 20% of member diagnoses won’t map to Hierarchical Condition Categories (HCCs) after October 1, 2025, putting millions in revenue at risk.
Coding errors also increase the risk of exposure to Risk Adjustment Data Validation (RADV) audits through extrapolation. The 2026 ICD-10-CM update impacts Risk Adjustment Factor (RAF) scores and CMS payments. With nine months to retrain providers, update systems, and align coding, your MA (Medicare Advantage) plan must act now.
Why ICD-10-CM Updates Matter for Medicare Advantage Plans?
Medicare Advantage reimbursement operates on a straightforward principle: accurate codes result in accurate payments. When CMS changes the code set, they’re changing your revenue dynamics.
Here’s what’s happening:
- Unspecified codes lose their value:
Generic codes like “heart failure, unspecified” won’t map to HCCs anymore - New combination codes replace old sequences:
Miss the new format, lose the RAF points - Specificity becomes mandatory:
No stage for (CKD) Chronic Kidney Disease? No HCC. No RAF. No payment.
Typically, for a plan with 100,000 members where 20% have affected conditions, a 3% drop in capture accuracy translates to thousands of missed HCCs. At average HCC weights and county base rates, you’re looking at a multi-million dollar annual impact.
The Codes That Will Cost You Money
The 2026 changes affect coding in several important ways. Below are common scenarios showing the differences between FY 2025 codes (valid through September 30, 2025) and the new FY 2026 codes (effective October 1, 2025), along with their impact on HCC mapping and RAF scoring. An extra column is included for Deleted/Converted Codes.
| Condition | FY 2025 Codes (Through Sept 30, 2025) | FY 2026 Codes (Effective Oct 1, 2025) | Impact on HCC Capture | RAF Effect (Provider/Coder Perspective) | Deleted/Converted Codes (Old code in use after Oct 1, 2025, will result in claim rejection/& no RAF credit) |
|---|---|---|---|---|---|
| Heart Failure | I50.9 – HF (Heart failure), unspecified | I50.2x / I50.3x – Specific systolic/diastolic heart failure with severity | Unspecified may no longer map under HCC v28; specific phenotypes/severity do | RAF increases when providers document HF type (e.g., HFrEF/HFpEF) and severity; coders must select the new, specific code to capture HCC. | I50.9 remains in ICD-10-CM but may not map to HCC v28 when unspecified; convert to I50.2x/I50.3x where clinically supported. |
| Diabetes with Neuropathy | E11.9 – Type 2 DM, no complication + G62.9 – Polyneuropathy, unspecified | E11.42 – Type 2 DM with diabetic polyneuropathy (combo code) | The combination code ensures linkage and reduces missed capture | RAF capture is more reliable with the combination code; separate coding or failure to link etiologies risks lost RAF. | Prior separate sequence is functionally converted to E11.42 for proper linkage/HCC capture; G62.9 alone typically does not map to an HCC. |
| Chronic Kidney Disease | N18.9 – CKD, unspecified | N18.4 – CKD Stage 4 (required stage) | Only staged CKD codes map under HCC v28 | RAF score increases when providers document CKD stage and coders apply it correctly. If the stage is not documented, unspecified CKD won't map | N18.9 retained but no HCC mapping when unspecified; convert to documented N18.x stage-specific codes. |
| Neuropathy (unspecified) | G62.9 – Polyneuropathy, unspecified | Link to diabetes (e.g., E11.42) or specify other etiology | Standalone unspecified neuropathy generally won't map to an HCC | RAF score is captured only when coders link neuropathy to diabetes. If providers or coders leave it as unspecified, the RAF point is lost | G62.9 retained but no HCC mapping as a standalone; convert by documenting/linking etiology. |
| Hypertension with Heart Disease | I10 – Essential hypertension + I50.9 – HF unspecified | I11.0 – Hypertensive heart disease with HF | Requires linkage per guidelines | RAF score increases when providers document the relationship ("with") and coders apply the correct sequence. If conditions are coded separately, RAF is missed | I10 + I50.9 sequence retained but should be converted to I11.0 when clinical linkage is present and documented. |
| Acute Myocardial Infarction (AMI) — subtype/phenotype specificity | I21.9 – Acute myocardial infarction, unspecified | I21.Ax / I21.Bx / I22.x variants specifying transmural vs. nontransmural, site, and STEMI/NSTEMI phenotypes | Specific AMI subtype/site codes map more reliably to HCCs tied to long-term cardiac risk | RAF capture improves when providers document AMI subtype (e.g., ST-elevation myocardial infarction,–non-ST-elevation) and affected site; unspecified AMI risks misclassification and missed HCC assignment | I21.9 retained but may not map optimally; convert to specific I21.x/I22.x subtype/site codes where documented. |
Footnote — New documentation rules (FY 2026)
- Diabetes remission: New codes (e.g., E11.A) for remission replace the prior default to E11.9.
- HIV: Updated sequencing rules for HIV disease vs. asymptomatic status.
- Affected areas: Use anatomy-specific codes when documented; “affected areas” only if detail is lacking.
- Diabetes complications: Must link conditions (e.g., neuropathy → diabetes) for correct combination coding.
- MEAT: Documentation must clearly support diagnoses for RADV audit defense.
Note: HCC Version 28 Mapping (Specific vs. Unspecified)
- FY 2025 (v24): Many unspecified codes are still mapped to HCCs.
- FY 2026 (v28): Most unspecified codes no longer map.
Bottom line: Specificity (stage, type, etiology) is required to preserve RAF.
Disclaimer :
SDOH Codes and RAF (Medicare Advantage)
FY 2025 & FY 2026: Social Determinants of Health (SDOH) Z-codes support equity reporting and care management but do not raise RAF scores.
Traditional Approaches No Longer Work
- Manual reviews can’t scale: Generally, it takes coder(s) 1,000+ days to review 20,000 members, and the new codes will stretch resources even thinner.
- Spreadsheets don’t validate: Excel can’t flag missing specificity, alert for combination codes, or build RADV audit trails. CMS requires documentation, not cells.
- Traditional Natural Language Processing (NLP) creates liability: Without MEAT (Monitor, Evaluate, Assess, Treat) evidence, “2026 readiness” collapses under audit scrutiny.
- Training won’t change behavior: Providers seeing 30+ patients daily can’t memorize rules. They need support at the point of care.
The solution → Explainable AI with clinical evidence for every code.
Coding Shifts Your Providers Can’t Ignore
Providers focus on care, not coding. Missing specificity—heart failure type, CKD stage, diabetes linkage erodes revenue. AI tools flag gaps in real time, ensuring accurate HCC/RAF capture.
With new Social Determinants of Health (SDOH) codes like housing instability or caregiver burnout, AI also ensures documentation supports benefits and CMS health equity reporting.
Challenges For MA Leaders
The Chief Financial Officer (CFO)’s Concern:
- Revenue at Risk: Outdated or unspecified codes drop RAF scores and reduce CMS payments.
- Revenue Opportunity: New, specific codes boost accuracy and increase average RAF.
Solution: Without defensible, evidence-based coding, these remain unquantified liabilities.
Explainable audit trails are the difference between loss and protection.
The Chief Operating Officer (COO)’s Problem: Another Operational Burden
2026 updates add challenges:
- 487 new codes
- Provider documentation demands
- EHR, claims, submission updates
- Expert workload increases
- Nine-month timeline
Solution: AI validation reduces manual reviews, easing provider friction and operational strain.
The Chief Information Officer (CIO)’s Security and Vendor Concerns
Too many tools mean integration, security, and ROI challenges. Traditional NLP adds compliance risk.
Solution: Explainable AI with MEAT evidence ensures secure, auditable documentation and vendor efficiency.
Leadership Action Plan: What to Do Now
Immediate Steps
- Analyze top 100 diagnoses; flag unspecified codes
- Calculate exposure: members, RAF at risk
- Check vendor contracts for 2026 compliance with audit trails
Provider Readiness
- Specialty updates: Cardiology (HF type/stage), Endocrinology (diabetes combos), Nephrology (CKD staging), Primary care (SDOH)
- Update templates for specificity, linkage, MEAT
- Deploy AI prompts, alerts, combo-code suggestions
Coding & System Prep
- Map deletions, train on combos, sequencing rules
- AI-assisted validation, monitor rejection rates
- Update EHR pick-lists, claims edits, HCC mapping, MEAT capture
Compliance (Ongoing)
- Pre-submission checks, audit trails, RADV defense, real-time dashboards
Benchmark Your Readiness With our Explainable AI-powered, customized Risk Adjustment Solution.
The Bottom Line
After October 1, unspecified codes drain revenue, missed linkages fail HCCs, and documentation gaps heighten RADV risk.
Forward-thinking plans deploy AI validation now. Nine months demand strategy and explainable AI, proving MEAT, building audit trails, protecting revenue, and targeting high-impact conditions decisively.
FAQs
MA reimbursement is tied to RAF scores from ICD-10-CM-coded HCCs. The 2026 updates
redefine mappings and coding rules, directly shaping plan revenue, compliance, and audit exposure.
Unspecified codes often won’t map to HCCs. Without details such as CKD stage or
heart failure type, providers risk missing HCC capture, RAF score loss, and revenue
shortfalls.
By requiring specificity—like heart failure type, CKD stage, or diabetes complications—new codes help coders map diagnoses correctly, strengthen RAF accuracy, and ensure payments align with members’ true disease burden.
Even a 1–3% drop in HCC capture across a large MA population equals millions in lost
revenue payments annually. Combined with RADV penalties, the financial exposure is
significant.
Leaders should refresh ICD-10-CM/HCC crosswalks, retrain providers, update EHR pick-lists, and strengthen audits. Coders can access official files via CMS’s ICD-10-CM webpage, Inpatient Prospective Payment System (IPPS) Final Rule tables and FY 2026 guidelines.
FY 2026 introduces 487 new codes, 38 revisions, and 28 deletions. The most significant
changes are in Chapter 19 (Injury/Poisoning) and Chapter 12 (Skin/Subcutaneous Tissue
(Disorders), demanding closer coding attention.
