E66.01
Morbid (severe) obesity due to excess calories
HCC risk adjustment mapping
CMS-HCC V28
Morbid Obesity
CMS-HCC ESRD V24
Morbid Obesity
Coding notes
Excludes 1 never coded together · Excludes 2 may co-exist
morbid (severe) obesity with alveolar hypoventilation (E66.2)
adiposogenital dystrophy (E23.6) lipomatosis dolorosa [Dercum] (E88.2) lipomatosis NOS (E88.2) Prader-Willi syndrome (Q87.11)
code to identify body mass index (BMI), if known, for adults (Z68.1-Z68.45) or pediatrics (Z68.5-)
obesity complicating pregnancy, childbirth and the puerperium, if applicable (O99.21-)
transitory endocrine and metabolic disorders specific to newborn (P70-P74)
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.
Official Guidelines for E66.01
FY 2026 ›Subsections
Sections that reference E66.01
- I.C.4.bObesity
The obesity codes in category E66, Overweight and obesity, include codes related to the cause of obesity, such as drug-induced obesity (E66.1), and codes related …
- I.C.4.b.1)Obesity class
The obesity class codes in subcategory E66.81, Obesity class, require a fifth character to convey the severity of obesity. …
Sections whose FY 2026 text names E66.01, its E66 category, or a range containing it — the chapter guidance above is the authoritative source.
Find E66.01 in the alphabetic index
5 index paths lead to this code