E66.9 ICD-10-CM Code: Obesity, unspecified
HCC Buddy Code Card
Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.
FY 2026 Apr update / Endocrine, nutritional and metabolic diseases (E00-E89) / Overweight, obesity and other hyperalimentation (E65-E68)
E66.9
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceObesity, unspecified
A general code for obesity when the specific type or cause is not documented or specified in the medical record.
CMS-HCC V28
N/A—
Not mapped
CMS-HCC V24
N/A—
Not mapped
ACA/HHS
N/A—
Not mapped
ESRD/PACE
N/A—
Not mapped
RXHCC
N/A—
Not mapped
Code Book Path
Inclusion Terms
Official- Obesity NOS
Excludes 2
Official- adiposogenital dystrophy (E23.6)
- lipomatosis dolorosa [Dercum] (E88.2)
- lipomatosis NOS (E88.2)
- Prader-Willi syndrome (Q87.11)
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for E66.9 in this effective period.
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for E66.9 in this effective period.
Code First
Official- obesity complicating pregnancy, childbirth and the puerperium, if applicable (O99.21-)
Use Additional
Official- code to identify body mass index (BMI), if known, for adults (Z68.1-Z68.45) or pediatrics (Z68.5-)
Code Also
OfficialICD-10-CM does not list Code Also instructions for E66.9 in this effective period.
Buddy Documentation Tip
Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →
Is E66.9 an HCC code?
No. E66.9 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.
- Code
- E66.9
- Description
- Obesity, unspecified
- HCC (V28)
- No CMS-HCC V28 mapping
- RAF
- —
- Billable
- Yes
- Payment year
- 2026
Coder workflow notes
Get the V28 RAF + MEAT cheat sheet
One printable page: confirm a code's V28 HCC status, its RAF weight, and the MEAT your note needs to make it stick. Free, no card.
Free PDF. No card. Unsubscribe anytime.
This code does not map to an HCC category in any model (V28, V24, ESRD, RxHCC).
What This Code Means
E66.9 is the ICD-10-CM diagnosis code for obesity, unspecified. A general code for obesity when the specific type or cause is not documented or specified in the medical record. E66.9 sits in the ICD-10-CM chapter for endocrine, nutritional and metabolic diseases (e00-e89), within the section covering overweight, obesity and other hyperalimentation (e65-e68).
E66.9 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.
This is the least specific obesity code; use only when no other E66 code can be determined.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for E66.9 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •This is the least specific obesity code; use only when no other E66 code can be determined
- •Query the provider if additional obesity details are available to assign a more specific code