Top 10 Most Common HCC Codes Every Coder Should Know
Master the most frequently encountered HCC codes in risk adjustment coding, from diabetes to heart failure, with mapping details and documentation tips.
By the HCC Buddy Coding Team
Updated: August 25, 2026
Top 10 Most Common HCC Codes Every Coder Should Know
Risk adjustment coders encounter certain HCC categories far more often than others. Mastering these high-frequency codes, and the ICD-10-CM codes that map to them, will make you faster, more accurate, and more valuable to your organization.
This list is based on the CMS-HCC V28 model, which is being phased in for Payment Year 2026. The underlying mapping file is the CMS 2026 risk-adjustment model software and ICD-10 mappings release.
1. HCC 37, Diabetes with Chronic Complications
Diabetes is the single most commonly coded HCC category. In V28, most diabetes complications consolidate under HCC 37.
Key ICD-10-CM codes:
- E11.22, Type 2 diabetes mellitus with diabetic chronic kidney disease
- E11.319, Type 2 diabetes mellitus with unspecified diabetic retinopathy without macular edema
- E11.42, Type 2 diabetes mellitus with diabetic polyneuropathy
Note: E11.65 (Type 2 diabetes with hyperglycemia) maps to HCC 38, not HCC 37. Hyperglycemia is not a chronic complication.
Documentation tip: Always capture the type of diabetes, the specific complication, and laterality where applicable.
2. HCC 226 / 225 / 224, Heart Failure (acuity-based split)
Heart failure remains one of the highest-weighted HCC categories, reflecting the significant cost of managing these patients.
Key ICD-10-CM codes:
- I50.22, Chronic systolic (systolic) heart failure
- I50.32, Chronic diastolic (diastolic) heart failure
- I50.42, Chronic combined systolic and diastolic heart failure
- I50.82, Biventricular heart failure
Documentation tip: Specify acuity (acute, chronic, or acute-on-chronic) and type (systolic, diastolic, or combined). I50.9 (heart failure, unspecified) maps to HCC 226 in V28. However, it is the lowest acuity tier. Acute presentations map to HCC 225 and acute-on-chronic presentations map to HCC 224.
3. HCC 280, Chronic Obstructive Pulmonary Disease
Chronic Obstructive Pulmonary Disease is consistently among the top coded conditions in Medicare Advantage populations.
Key ICD-10-CM codes:
- J44.1, Chronic obstructive pulmonary disease with acute exacerbation
- J44.0, Chronic obstructive pulmonary disease with acute lower respiratory infection
- J43.9, Emphysema, unspecified
Documentation tip: Document whether the patient is in stable state or experiencing an exacerbation. Capture any coexisting conditions like Asthma.
4. HCC 238, Atrial Fibrillation
Atrial fibrillation is extremely common in elderly populations and maps to HCC 238 in V28.
Key ICD-10-CM codes:
- I48.0, Paroxysmal atrial fibrillation
- I48.2, Chronic atrial fibrillation
- I48.91, Unspecified atrial fibrillation
Documentation tip: Specify the type of atrial fibrillation (paroxysmal, persistent, chronic/permanent). Also document whether it is controlled or uncontrolled.
5. HCC 48, Morbid Obesity
Morbid obesity maps to HCC 48 in V28 and is frequently encountered.
Key ICD-10-CM codes:
- E66.01, Morbid (severe) obesity due to excess calories
- Z68.41–Z68.45, Body mass index 40.0 and above (use as secondary code)
Documentation tip: Always pair E66.01 with the specific Body Mass Index Z code. The Body Mass Index must be documented in the same encounter.
6. HCC 226, Hypertensive Heart Failure Combinations
When hypertension and heart failure are documented together, the combination codes also map into the V28 heart failure family (HCC 226 for chronic/unspecified presentations).
Key ICD-10-CM codes:
- I11.0, Hypertensive heart disease with heart failure, maps to HCC 226
- I13.0, Hypertensive heart and chronic kidney disease with heart failure, maps to HCC 226
Documentation tip: When a patient has both hypertension and heart failure, code the combination code. CMS presumes a causal relationship between hypertension and heart disease. There is no separate "HCC 85" for heart failure in V28; all I50.x and hypertensive heart failure combinations map to the acuity-based family (HCC 224/225/226).
7. HCC 20, Lung, Pancreatic, and Other Severe Cancers
Active malignancies carry some of the highest RAF weights in the model.
Key ICD-10-CM codes:
- C25.9, Malignant neoplasm of pancreas, unspecified, maps to HCC 20
- C34.90, Malignant neoplasm of unspecified part of bronchus or lung, maps to HCC 20
- C18.9, Malignant neoplasm of colon, unspecified, maps to the lower-tier HCC 22 (Bladder, Colorectal, and Other Cancers), not HCC 20
Documentation tip: Only code active malignancies. If the cancer is in remission, history of, or has been excised, use the appropriate Z85 history code instead, which typically does not map to an HCC.
8. HCC 327, Chronic Kidney Disease, Stage 4
Advanced chronic kidney disease stages carry significant HCC weight due to the cost of managing these patients.
Key ICD-10-CM codes:
- N18.4, Chronic kidney disease, stage 4 (severe), maps to HCC 327
- N18.5, Chronic kidney disease, stage 5, maps to HCC 326
- N18.6, End stage renal disease, maps to HCC 326
Documentation tip: Document the specific stage. N18.4 (Stage 4) maps to HCC 327, while N18.5 (Stage 5) and N18.6 (ESRD) map to HCC 326. "Chronic kidney disease" without a stage defaults to N18.9 (unspecified), which does not map to a payment HCC in V28.
9. HCC 383, Chronic Ulcer of Skin, Except Pressure
Chronic skin ulcers are common in diabetic and vascular patients and map to their own HCC.
Key ICD-10-CM codes:
- L97.529, Non-pressure chronic ulcer of other part of left foot with unspecified severity
- L97.919, Non-pressure chronic ulcer of unspecified part of unspecified lower leg
Documentation tip: Capture the exact location, laterality, and severity (limited to skin breakdown, fat layer exposed, necrosis of muscle, necrosis of bone, etc.).
10. HCC 155, Major Depressive Disorder (Moderate/Severe)
Mental health conditions, particularly major depression, are increasingly captured in risk adjustment.
Key ICD-10-CM codes:
- F32.1, Major depressive disorder, single episode, moderate
- F33.1, Major depressive disorder, recurrent, moderate
- F33.2, Major depressive disorder, recurrent, severe without psychotic features
Documentation tip: Specify single episode vs. recurrent, and severity (mild, moderate, severe). Document whether it is with or without psychotic features.
Quick-Reference Table
| HCC (V28) | Category | Common ICD-10 | RAF Weight |
|---|---|---|---|
| 37 | Diabetes with Chronic Complications | E11.22 | [see RAF tool] |
| 226 | Heart Failure (Chronic/Unspecified) | I50.22, I50.32 | [see RAF tool] |
| 280 | Chronic Obstructive Pulmonary Disease | J44.1, J43.9 | [see RAF tool] |
| 238 | Atrial Fibrillation | I48.0, I48.2 | [see RAF tool] |
| 48 | Morbid Obesity | E66.01 | [see RAF tool] |
| 20 | Lung & Other Severe Cancers | C25.9, C34.90 | [see RAF tool] |
| 327 | Chronic Kidney Disease Stage 4 | N18.4 | [see RAF tool] |
| 383 | Chronic Ulcer of Skin | L97.529 | [see RAF tool] |
| 155 | Major Depressive Disorder (Moderate/Severe) | F32.1, F33.1 | [see RAF tool] |
*Note: Coefficients are segment-specific and year-versioned. Use the source-labeled public HCC reference pages for the applicable model and segment; those coefficients are references, not a member score.*
Use HCC Buddy to Verify Mappings
Instead of memorizing code-to-HCC mappings, use HCC Buddy's encoder to check the source-backed mapping status, model period, and segment-labeled coefficient context when available.
Free resource: Download the HCC Coding Cheat Sheet, a printable V28 quick reference with top HCC categories and documentation tips.
Frequently asked questions
What is HCC 37 and which ICD-10 codes map to it?
HCC 37 is the Diabetes with Chronic Complications category in the CMS-HCC V28 model, carrying a community RAF weight of approximately 0.166. It is the single most commonly coded HCC category in risk adjustment. Key ICD-10-CM codes include E11.65 (Type 2 diabetes with hyperglycemia), E11.22 (Type 2 diabetes with diabetic chronic kidney disease), E11.319 (Type 2 diabetes with unspecified diabetic retinopathy without macular edema), and E11.42 (Type 2 diabetes with diabetic polyneuropathy). Always capture the type of diabetes, the specific complication, and laterality where applicable.
Why does 'heart failure unspecified' (I50.9) cause problems in HCC coding?
I50.9 (heart failure, unspecified) maps to HCC 226 and does carry RAF value, but it creates two problems. First, it is a red flag for RADV auditors who expect documentation of type (systolic vs. diastolic) and acuity (acute vs. chronic). Second, it represents undercoding whenever the chart contains an echocardiogram or cardiology note identifying the specific type. The fix is to query the provider for systolic, diastolic, or combined classification and acute vs. chronic acuity, then assign I50.22 (chronic systolic) or I50.32 (chronic diastolic) as supported.
What is the most important documentation tip for CKD HCC coding?
The single most important documentation tip for chronic kidney disease HCC coding is staging. Coding N18.9 (CKD, unspecified stage) does not map to a payment HCC in CMS-HCC V28. Only specific stages carry HCC value: N18.4 (Stage 4) maps to HCC 327, and N18.5 (Stage 5) and N18.6 (ESRD) map to HCC 326. The provider must document the GFR-based CKD stage in the encounter note. Query the provider whenever the chart shows a GFR value but the documented stage is unspecified.
How should major depression be coded to capture the correct HCC?
Major depression HCC coding requires documenting severity (mild, moderate, severe) and episode pattern (single episode vs. recurrent). The key codes are F32.1 (major depressive disorder, single episode, moderate), F33.1 (recurrent, moderate), and F33.2 (recurrent, severe without psychotic features), all of which map to HCC 155 in V28. F32.9 (major depressive disorder, unspecified) may not map to a payment HCC. The provider must specify severity and episode type in the encounter note to support the specific code.
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HCC Buddy Coding Team
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Every HCC Buddy article is checked against the current CMS-HCC model and the active FY ICD-10-CM tabular release before it publishes.
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