What Is HCC Coding?

Hierarchical Condition Category (HCC) coding is a risk adjustment methodology used by the Centers for Medicare and Medicaid Services (CMS) to predict future healthcare costs for patients. Medical coders play a critical role in this process by ensuring that every diagnosis is accurately captured using ICD-10-CM codes, which then map to specific HCC categories.

Why HCC Coding Matters

HCC coding directly impacts how much Medicare Advantage plans are reimbursed for each patient. When a patient's chronic conditions are accurately documented and coded, the plan receives appropriate funding to cover that patient's expected healthcare needs.

Key reasons HCC coding is essential:

Accurate reimbursement — Plans receive funding that matches the true health burden of their population

Quality of care — Complete documentation ensures care teams understand each patient's full clinical picture

Regulatory compliance — CMS audits require that every coded condition is supported by clinical documentation

RAF score accuracy — The Risk Adjustment Factor score determines per-member-per-month payments

How ICD-10-CM Codes Map to HCCs

Not every ICD-10-CM code maps to an HCC. Of the approximately 72,000 ICD-10-CM codes, only a subset are HCC-relevant. The mapping process works as follows:

1. Provider documents a condition during a face-to-face encounter

2. Coder assigns the most specific ICD-10-CM code supported by documentation

3. The code is crosswalked to the CMS-HCC model (V24 or V28)

4. Each HCC has a weight (coefficient) that contributes to the patient's RAF score

5. The RAF score determines the plan's reimbursement for that member

Example

A patient with Type 2 Diabetes Mellitus with diabetic chronic kidney disease would be coded as:

E11.22 — Type 2 diabetes mellitus with diabetic chronic kidney disease

This maps to HCC 18 (Diabetes with Chronic Complications) in the V28 model

HCC 18 carries a RAF weight that increases the patient's risk score

HCC Coding Models: V24 vs V28

CMS is transitioning from the V24 model to the V28 model. In 2026, the blended model uses:

V24 weight: 33%

V28 weight: 67%

Key differences in V28:

Many HCC categories were consolidated or removed

Some conditions that were HCC-relevant in V24 are no longer mapped in V28

New HCC categories were added for conditions like substance use disorders

RAF weights were recalibrated across all categories

MEAT Criteria for HCC Coding

For an HCC to be captured, the documentation must meet the MEAT criteria:

Monitoring — The provider is monitoring the condition (labs, exams, assessments)

Evaluating — The provider is evaluating the condition's status or progression

Assessing — The provider documents their clinical assessment of the condition

Treating — The provider is actively treating the condition (medications, therapies, referrals)

Simply listing a condition in the past medical history is not sufficient for HCC capture.

How HCC Buddy Helps

HCC Buddy is built specifically for HCC coders. Every ICD-10-CM code in our encoder shows:

Whether the code maps to an HCC (and which one)

The RAF weight for both V24 and V28 models

Includes, Excludes 1, and Excludes 2 notes

An AI coding assistant that can answer MEAT criteria and coding guideline questions

Try it free — search any ICD-10 code and see the HCC mapping instantly at hccbuddy.com/encoder.

Free resource: Download the HCC Coding Cheat Sheet — a printable V28 quick reference with top HCC categories and documentation tips.

What Is HCC Coding? A Complete Guide for 2026