Top V28 Coding Pitfalls That Affect Risk Scores and Claims Pricer Accuracy

The CMS Hierarchical Condition Category (HCC) risk adjustment model plays a pivotal role in how Medicare Advantage (MA) plans reimburse healthcare providers. With the rollout of Version 28 (V28) of the HCC model, providers are entering a new era of stricter coding standards and heightened audit scrutiny. Accurate coding is essential for capturing patient complexity, ensuring appropriate payments, and avoiding compliance risks. However, many healthcare organizations still rely on outdated coding practices inherited from earlier models like V24. This guide explores the most critical coding pitfalls under V28 and offers practical strategies to help coding teams and clinicians avoid them.

🔄 What Changed in V28?

The V28 model introduces major revisions intended to increase coding precision, reduce upcoding, and reflect modern clinical standards:

• Overhaul of HCC categories for clinical accuracy

• Elimination of 2,000+ diagnosis codes no longer considered predictive

• Consolidation and reclassification of ICD-10 codes

• Shift from RAPS to 100% encounter data by 2026

Why it matters: Incorrect or outdated coding can result in lost reimbursement, failed audits, and financial risk. Staying informed is key.

⚠️ Common Coding Pitfalls to Avoid

1. Using Deleted or Declassified ICD-10 Codes Many codes that previously mapped to HCCs under V24 have been retired or declassified in V28. Example: ICD-10 code M54.5 (low back pain) was removed from risk scoring due to low predictive value. Risk: Using invalid codes won’t contribute to the patient’s risk score. Best Practice: Always verify ICD-10 codes against the latest V28-aligned HCC mappings. Tools like CMS's updated Web Pricer and commercial coding software can help.
   

2. Inadequate Documentation to Support Diagnoses CMS requires that diagnoses are documented as "monitored, evaluated, assessed, or treated" (MEAT criteria). Pitfall: Simply listing a diagnosis without contextual documentation won’t support risk adjustment. Example: Coding for COPD without notes on spirometry, symptoms, or treatment plan. Solution: Train clinicians to document the clinical context. Use EHR prompts to ensure MEAT criteria is satisfied.
   

3. Missing Hierarchical Conditions (e.g., Severity Levels) V28 relies on specificity, including severity gradations. Example: Failing to specify "Diabetes with chronic complications" results in underreporting risk. Impact: Lower HCC score and reduced payments. Tip: Code to the highest level of specificity, especially for chronic conditions like:
   

   • Diabetes (e.g., E11.22 for diabetes with CKD)

   • CKD (e.g., N18.4 for stage 4 CKD)

   • CHF (e.g., I50.32 for diastolic heart failure)
     

4. Not Capturing All Active Chronic Conditions Annually CMS requires annual refresh of every HCC-related condition. Mistake: Assuming a one-time diagnosis carries over year to year. Example: A patient with COPD diagnosed in 2023 must have it re-documented in 2024 and 2025 for risk adjustment purposes. Fix: Establish a standard annual wellness workflow that includes a complete HCC review.
   

5. Incomplete Encounter Data Submissions With CMS transitioning to 100% encounter data, incomplete or incorrect claims submissions pose a huge risk. Problem: If a diagnosis is not transmitted accurately in encounter data, it will not be scored. Checklist:
   

   • Ensure encounter data is linked to provider notes

   • Train billers on clean claim submission

   • Confirm that clearinghouses are formatting diagnoses properly
     

6. Relying on Outdated Templates or EHR Prompts Many EHR systems haven’t been updated to reflect V28 HCC logic. Issue: EHRs may still prompt documentation for diagnoses that no longer count. Solution: Collaborate with your IT or EMR vendor to integrate V28-compatible prompts and dropdowns.
   

7. Undercoding Due to Fear of Audits Some organizations err on the side of extreme caution, excluding valid high-risk diagnoses for fear of audit penalties. Consequence: Underreported patient complexity = reduced revenue. Recommendation: Conduct routine coding audits to validate high-risk diagnoses. Support coders with clinical training, not fear.
   

📈 Real-World Coding Audit Insights

From recent internal audits across MA provider groups:

• 1 in 4 patient charts lacked full documentation for all active chronic conditions

• 35% of diabetes-related diagnoses missed renal or circulatory complications

• Over 40% of non-specific codes still in use, despite removal in V28
  

This underscores the urgent need for coding literacy under the V28 model. ✅ Strategies to Improve Risk Adjustment Coding

• Train all clinical and coding staff on V28 updates

• Implement risk score tracking dashboards

• Use clinical decision support tools to flag missing conditions

• Set up quarterly documentation audits

• Collaborate with Medicare Advantage Organizations (MAOs) to align on data requirements
  

🔑 Final Takeaway

The transition to V28 is not just a coding update—it’s a call to action for providers to modernize their risk capture workflows. Avoiding common pitfalls can help practices:

• Protect against revenue leakage

• Improve audit compliance

• Ensure accurate patient risk stratification

By embedding V28-aligned best practices into daily documentation and coding routines, healthcare organizations can adapt confidently and successfully Learn the most common coding errors under CMS's V28 HCC risk adjustment model and how providers can stay compliant and maximize reimbursement accuracy.