E66.81 Obesity class

The ICD-10-CM code for Obesity class is E66.81 (FY2026). It is a non-billable category code — select a more specific code below for claims.

Classification

Chapter

4: Endocrine, nutritional and metabolic diseases (E00-E89)

Section

E65-E68: Overweight, obesity and other hyperalimentation (E65-E68)

Category E66

14 codes (10 billable)

FY2026 Status

Introduced in FY2025

Official Coding Guidelines

E66.81 obesity class: 5th character required; documentation; coding rules

1) Obesity class The obesity class codes in subcategory E66.81, Obesity class, require a fifth character to convey the severity of obesity. The obesity class should be documented in the medical record by the provider for these codes to be assigned. The obesity class codes can be reported with other obesity codes in the classification found in Chapters 4 and 15 to fully describe the condition. However, if both class 3 obesity and morbid obesity are documented, only a code for class 3 obesity should be assigned as it is more specific.

Diabetes mellitus (TOC entry)

a. Diabetes mellitus ................................................................................................................... 39

Source: CMS — ICD-10-CM Official Guidelines for Coding and Reporting, FY2026

References

• CMS — ICD-10-CM Official Code Set and Guidelines, FY2026
• CDC/NCHS — ICD-10-CM Files and Browser Tool