MCMedicalCodingSoftware
E66.813

E66.813Obesity, class 3

Billable / specific codeICD-10-CM

E66.813 is a billable, specific ICD-10-CM code for obesity, class 3. It is valid for submission on a claim.

Excludes2 inherited from the categories above E66.813

Also inherited, and the opposite of Excludes1: these conditions are not part of E66.813, but a patient can have both, so you may code both.

Written on E66 Overweight and obesity

  • adiposogenital dystrophy (E23.6)
  • lipomatosis dolorosa [Dercum] (E88.2)
  • lipomatosis NOS (E88.2)
  • Prader-Willi syndrome (Q87.11)

Other codes that can never be billed with E66.813

These codes carry an Excludes1 note pointing at E66.813. The conflict binds both ways, but ICD-10-CM only writes it down on one side — so you would not find this by reading E66.813 alone.

  • R63.5Abnormal weight gain

Risk adjustment

E66.813 risk-adjusts. Under the CMS-HCC V28 model it maps to this category:

  • HCC 48 Morbid Obesity0.186 RAF

Coefficient shown for the Community Non-dual Aged segment. A higher HCC in the same hierarchy will suppress this one, so capturing it does not always add score.

Medicare coverage

E66.813 is named in 15 Medicare coverage policies 15 listing it as supporting medical necessity. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.

  • A54923Billing and Coding: Bariatric Surgery for Treatment of Co-Morbidities Conditions Related to Morbid Obesity
  • A56852Billing and Coding: Laparoscopic Sleeve Gastrectomy for Severe Obesity
  • A57065Billing and Coding: Outpatient Psychiatry and Psychology Services
  • A57145Billing and Coding: Surgical Management of Morbid Obesity

How E66.813 is indexed

Coders do not find codes by browsing the tabular list — they look them up in the alphabetic index, under the word the physician wrote. These are the index entries that lead here, so you can see which chart wordings map to E66.813.

  • Obesityclass3

The condition this code belongs to

Every code for the condition on one page, which one applies when, and the mistake coders make with it.

Code history

What changed, and when. Derived by diffing consecutive CMS release files — which matters when you are defending a code assigned under an earlier edition.

  • addedFY2024-FY2026

    Obesity, class 3

Related codes at this level

Codes that share E66.81. If E66.813 is not quite right, the correct code is usually one of these.

Questions about E66.813

Is E66.813 a billable ICD-10-CM code?
Yes. E66.813 is a billable, specific ICD-10-CM code and is valid for submission on a claim.
Where does E66.813 sit in the tabular list?
Endocrine, nutritional and metabolic diseases (E00-E89), in the block Overweight, obesity and other hyperalimentation (E65-E68).
ICD-10-CMFY2026-Apr· effective April 1, 2026

Loaded directly from the CMS/NCHS ICD-10-CM public-domain release — see data sources and our editorial policy. If this page disagrees with the CMS tabular list, this page is wrong. Reference information for professional coders; not medical or billing advice.