E66.01 vs E66.2
E66.01 (Morbid (severe) obesity due to excess calories) compared with E66.2 (Morbid (severe) obesity with alveolar hypoventilation), from the official CMS tabular data. Do not report these codes together: the official tabular list marks them Excludes1.
Can these codes be reported together?
No — do not report together. E66.01 carries an Excludes1 note covering E66.2: “morbid (severe) obesity with alveolar hypoventilation (E66.2)”
Sole exception: when the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).
Side by side
| E66.01Morbid (severe) obesity due to excess calories | E66.2Morbid (severe) obesity with alveolar hypoventilation | |
|---|---|---|
| Billing status | Billable | Billable |
| Classification | E00-E89 — Endocrine, Nutritional and Metabolic Diseases (E00-E89) | E00-E89 — Endocrine, Nutritional and Metabolic Diseases (E00-E89) |
| Definition | Morbid (severe) obesity due to excess calories is a billable ICD-10-CM diagnosis code (E66.01). | Morbid (severe) obesity with alveolar hypoventilation is a billable ICD-10-CM diagnosis code (E66.2). |
| Includes | — | Obesity hypoventilation syndrome (OHS) Pickwickian syndrome |
| Use additional code | code to identify body mass index (BMI), if known, for adults (Z68.1-Z68.45) or pediatrics (Z68.5-) | code to identify body mass index (BMI), if known, for adults (Z68.1-Z68.45) or pediatrics (Z68.5-) |
| Code first | obesity complicating pregnancy, childbirth and the puerperium, if applicable (O99.21-) | obesity complicating pregnancy, childbirth and the puerperium, if applicable (O99.21-) |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources