Condition guide
Morbid Obesity HCC Coding Guide
Morbid Obesity (e.g. E66.2) maps to HCC 48 (Morbid Obesity) under the CMS-HCC V28 risk adjustment model, with a community, non-dual, aged RAF weight of 0.186; V28 reached 100% phase-in for payment year 2026. E66.09, other obesity due to excess calories, is non-HCC under V28.
Quick Facts
HCC Categories
HCC 48, Morbid Obesity
RAF Weight Range
0.186
Community, non-dual, aged (V28)
Model
CMS-HCC V28 (PY2026, 100% phase-in)
7 ICD-10 codes map to payment HCCs
How coders write it
Chart notes, problem lists, and queries rarely spell out Morbid Obesity. The shorthand you will actually see:
Whatever the note calls it, the payment question is the same: how the ICD-10-CM code resolves to a payment HCC.
What HCC category does Morbid Obesity map to under V28?
Obesity affects over 42% of US adults, and morbid (severe) obesity is a payment condition under the CMS-HCC V28 model. General obesity codes do not map to a payment HCC, but the morbid obesity codes do. Under V28, the morbid obesity diagnosis codes E66.01 (due to excess calories), E66.2 (with alveolar hypoventilation), and E66.813 (obesity, class 3) all map to HCC 48 (Morbid Obesity), as do the high-BMI codes Z68.41 through Z68.45 (BMI 40.0 and above). HCC 48 carries a community non-dual aged RAF of 0.186. One coding-guideline limit matters here: a BMI Z-code can only be reported alongside an associated provider-documented diagnosis such as obesity, so the clinical obesity diagnosis still needs to be in the note. Query the provider when the BMI indicates severe obesity but the note only says "obesity."
ICD-10 to HCC Mapping
| ICD-10 Code | Description | Billable | HCC Mapping |
|---|---|---|---|
| E66.01 | Morbid (severe) obesity due to excess calories | Yes | HCC 48 |
| E66.2 | Morbid (severe) obesity with alveolar hypoventilation | Yes | HCC 48 |
| E66.09 | Other obesity due to excess calories | Yes | No HCC (not risk-adjusting under V28) |
| E66.1 | Drug-induced obesity | Yes | No HCC (not risk-adjusting under V28) |
| Z68.41 | Body mass index [BMI] 40.0-44.9, adult | Yes | HCC 48 |
| Z68.42 | Body mass index [BMI] 45.0-49.9, adult | Yes | HCC 48 |
| Z68.43 | Body mass index [BMI] 50.0-59.9, adult | Yes | HCC 48 |
| Z68.44 | Body mass index [BMI] 60.0-69.9, adult | Yes | HCC 48 |
| Z68.45 | Body mass index [BMI] 70 or greater, adult | Yes | HCC 48 |
| E66.8 | Other obesity | Yes | No HCC (not risk-adjusting under V28) |
RAF weights are community, non-dual, aged base coefficients from the CMS-HCC V28 model (PY2026). Verify against the latest CMS rate announcement for payment calculations.
HCC Buddy maps Morbid Obesity from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coder workflow notes
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Documentation Tips
Document the clinical diagnosis of 'morbid obesity' or 'severe obesity', a BMI code alone does not support an HCC-mapped diagnosis code.
Always include the current BMI value in the encounter note alongside the obesity diagnosis.
Use E66.01 (morbid obesity due to excess calories) as the primary obesity diagnosis code for HCC capture.
Document the treatment plan: dietary counseling, exercise prescription, medication management, or bariatric surgery evaluation.
When BMI is 40+, query the provider if the assessment only says 'obesity' without specifying 'morbid' or 'severe'.
Document obesity-related comorbidities (sleep apnea, osteoarthritis, GERD) as they support the medical necessity of the obesity diagnosis.
If the patient has had bariatric surgery, document the procedure status and current BMI to determine if morbid obesity is still appropriate.
MEAT documentation examples for Morbid Obesity
A diagnosis only counts toward risk adjustment when the encounter note shows the provider engaged with it. These are the kinds of entries that satisfy the MEAT documentation standard for Morbid Obesity:
MMonitor
“Weight 287 pounds, BMI 43.1, up 4 pounds since the last visit.”
“Sleep study reviewed: AHI 32, on CPAP nightly.”
“Monthly weight log reviewed with patient.”
EEvaluate
“Exam notable for BMI 43.1; waist circumference 48 inches.”
“Screened for weight-related comorbidities: GERD and OSA present.”
“Candidacy for bariatric surgery referral reviewed.”
AAssess
“Morbid obesity, BMI 43.1, with obstructive sleep apnea.”
“Class 3 obesity, weight trending up despite dietary changes.”
“Morbid obesity with alveolar hypoventilation, stable on BiPAP.”
TTreat
“Started semaglutide, titrating to therapeutic dose.”
“Referred to bariatric surgery program and dietitian.”
“Structured weight management program; follow-up in four weeks.”
Common Coding Mistakes
Coding E66.09 (other obesity) instead of E66.01 (morbid obesity) when the BMI is 40+ and the provider documents severe/morbid obesity.
Reporting a BMI Z-code (Z68.4x) without an associated provider-documented obesity diagnosis, ICD-10-CM guidelines require the clinical diagnosis to be present before the BMI code can be assigned.
Failing to query the provider when the BMI clearly indicates morbid obesity but the documentation only states 'obesity.'
Not recapturing morbid obesity annually, this is a chronic condition that requires documentation at each encounter for risk adjustment.
V24 to V28 Changes
Under V28, morbid obesity maps to HCC 48 (Morbid Obesity), with a community non-dual aged RAF of 0.186. Coders moving from V24 should note the category was renumbered (V24 placed morbid obesity in HCC 22 at 0.250), so the weight came down along with the number. The codes that feed HCC 48 are the morbid and class 3 obesity diagnoses (E66.01, E66.2, E66.813) plus the high-BMI codes Z68.41 to Z68.45 (BMI 40.0 and above). The broader obesity codes, including E66.09 (other obesity due to excess calories), E66.1 (drug-induced obesity), E66.8 entries other than class 3, and E66.9 (obesity, unspecified), remain non-payment codes. Because ICD-10-CM only allows a BMI Z-code when an associated obesity diagnosis is documented, capturing the specific morbid or class 3 obesity diagnosis is what anchors the HCC.
| Aspect | V24 (through PY2025) | V28 (PY2026) |
|---|---|---|
| Morbid obesity (E66.01, E66.2) | HCC 22, Morbid Obesity, RAF 0.250 | HCC 48, Morbid Obesity, RAF 0.186 |
| BMI 40+ Z-codes (Z68.41 to Z68.45) | HCC 22, RAF 0.250 | HCC 48, RAF 0.186 |
| Class 3 obesity (E66.813) | HCC 22 | HCC 48 |
| Other obesity (E66.09, E66.1, E66.9) | No payment HCC | No payment HCC |
RAF values are community, non-dual, aged base coefficients for each model's payment year. To see what these weights do to a real patient total, run the codes through the RAF score calculator.
Morbid Obesity coding FAQs
What BMI qualifies for morbid obesity coding?
The BMI Z-codes that map to HCC 48 start at 40.0: Z68.41 (40.0 to 44.9) through Z68.45 (70 or greater). The Z-code alone is not enough, though. ICD-10-CM requires an associated provider-documented diagnosis before a BMI code can be reported, so the note needs the clinical morbid or severe obesity diagnosis (E66.01, E66.2, or E66.813) to anchor the capture.
Does E66.9 (obesity, unspecified) map to an HCC?
No, in either model. Unspecified and general obesity codes (E66.9, E66.09, E66.1) carry no payment HCC. When the chart shows a BMI of 40 or higher but the assessment only says obesity, a provider query for morbid or class 3 obesity is the compliant path to HCC 48.
Can you report a BMI Z-code without an obesity diagnosis?
No. ICD-10-CM guidelines allow BMI codes only when there is an associated, provider-documented diagnosis such as obesity or overweight, and coding guidance directs that BMI come from clinician documentation while the diagnosis itself comes from the provider. A Z68.4x code sitting alone in the claim is an audit flag, not an HCC.
Related Conditions
Related references
CMS-HCC V28 model
How the V28 categories, RAF weights, and hierarchy work for PY2026.
ICD-10 to HCC mapping
How an ICD-10-CM code resolves to a payment HCC under V28.
MEAT criteria
The documentation standard every coded condition must satisfy.
Add confirmed HCCs and review the full model total.
Sources
RAF weights are community, non-dual, aged base coefficients from the CMS-HCC V28 model (PY2026). Verify against the latest CMS Rate Announcement for payment.
Verified current to CMS-HCC V28, payment year 2026 — last reviewed July 16, 2026.
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