E66.811
Obesity, class 1
E66.811 (also written E66811) is a billable ICD-10-CM diagnosis code for obesity, class 1. It is part of the FY2027 code set, effective October 1, 2026. It is one of the 10 codes in category E66 (Overweight and obesity). The Alphabetic Index lists it under 1 entry. Its coding notes include a Code first instruction, a Use additional code instruction, 1 Excludes1 entry and 4 Excludes2 entries.
Guidelines tip
From the FY2027 Official Guidelines. ICD10Ref adds no rules of its own.
Obesity class codes depend on the provider documenting the class. If class 3 and morbid obesity are both documented, only class 3 is assigned.
Code first
If the underlying condition listed here is present and known, sequence it first.
Use additional code
Add the listed code as a secondary code, if known.
Excludes1
Not coded here. The listed conditions generally should not be reported together.
Excludes2
Not included here. Both codes may be reported if the patient has both conditions.
Care settings
How CMS programs treat this code. These are CMS claim edits and list entries, not coverage or eligibility rules.
Home Health Primary
Accepted as the primary (principal) diagnosis on a home health claim. The Home Health Grouper assigns it to the MMTA - Other clinical group.
Source: CMS Home Health Grouper Software v07.2.26, effective October 1, 2026Notes
Also from chapter/block level (1 note)
- All neoplasms, whether functionally active or not, are classified in Chapter 2. Appropriate codes in this chapter (i.e. E05.8, E07.0, E16-E31, E34.-) may be used as additional codes to indicate either functional activity by neoplasms and ectopic endocrine tissue or hyperfunction and hypofunction of endocrine glands associated with neoplasms and other conditions classified elsewhere.
Alphabetic Index terms
Terms the official Alphabetic Index lists for this code. 1 entry