E66.01 — Morbid (severe) obesity due to excess calories
Is E66.01 billable?
Yes — E66.01 is billable for FY2027. E66.01 is a valid, billable ICD-10-CM code at the highest level of specificity in its branch. E66.01 may be submitted for encounters from October 1, 2026 through September 30, 2027.
E66.01 at a glance
| Code | E66.01 |
|---|---|
| Description | Morbid (severe) obesity due to excess calories |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
Which MS-DRGs does E66.01 group to?
E66.01 sits in MDC 10 and helps define the logic of 2 MS-DRGs (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.
- 640Miscellaneous Disorders of Nutrition, Metabolism, Fluids and Electrolytes with MCCmedical
- 641Miscellaneous Disorders of Nutrition, Metabolism, Fluids and Electrolytes without MCCmedical
How is E66.01 listed in the Alphabetic Index?
These are the routes through the Alphabetic Index that lead to E66.01. They show the wording a clinician may have documented, which often differs from the Tabular description.
- Obesity › morbid
- Obesity › severe
- Obesity › morbid › due to excess calories
- Obesity › due to › excess calories › morbid
- Obesity › due to › excess calories › severe
Excludes1 — never code together
The conditions below can never be reported together with E66.01 on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
- morbid (severe) obesity with alveolar hypoventilation (E66.2)
Excludes1 — never code together — inherited from Chapter 4
The conditions below can never be reported together with E66.01 on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
- transitory endocrine and metabolic disorders specific to newborn (P70-P74)
Code first — inherited from E66
The underlying condition below must be sequenced before E66.01. E66.01 describes a manifestation and cannot be the principal or first-listed diagnosis.
- obesity complicating pregnancy, childbirth and the puerperium, if applicable (O99.21-)
Use additional code — inherited from E66
Report an additional code alongside E66.01 to fully describe the condition. E66.01 is sequenced first.
Excludes2 — not included here — inherited from E66
The conditions below are not part of E66.01, but a patient may have both at the same time. When documentation supports it, E66.01 and the excluded code may both be reported.
How long has E66.01 existed?
E66.01 has been in ICD-10-CM since at least FY2016, the earliest fiscal year on record here.
Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.