2027 ICD-10-CM Diagnosis Code E66.9Obesity, unspecified
ICD-10-CM Codes›E00–E89›E65-E68›E66
- Billable — Valid for Submission
- Chronic Condition
E66.9 is a billable ICD-10-CM diagnosis code for obesity, unspecified. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 640 through 641. The code is flagged as a questionable admission, since it rarely justifies inpatient admission on its own. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Obesity.
Code Identity
Code Classification
Code EditsBilling
Medicare Code Editor checks that affect claim validity for E66.9.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Benign intracranial hypertension
- Blood magnesium below reference range
- Blood magnesium outside reference range
- Body mass index 30+ - obesity
- Central obesity
- Choroideremia
- Choroideremia with deafness and obesity syndrome
- Cognitive impairment, coarse facies, heart defects, obesity, pulmonary involvement, short stature, skeletal dysplasia syndrome
- Colobomatous microphthalmia
- Colobomatous microphthalmia, obesity, hypogenitalism, intellectual disability syndrome
- Congenital mixed conductive and sensorineural hearing loss
- Deafness, encephaloneuropathy, obesity, valvulopathy syndrome
- Difficulty maintaining weight loss
- Excess subcutaneous fat
- Fetal disorder due to maternal obesity
- Fetal disorder due to maternal obesity with adult body mass index 30 or greater but less than 40
- Fetal disorder due to maternal obesity with adult body mass index equal to or greater than 40
- Generalized obesity
- Genetic syndromic childhood obesity
- Has seen dietitian - obesity
- Hereditary choroidal dystrophy
- Impaired glucose tolerance in obese
- Increased body mass index
- Intellectual disability, obesity, brain malformation, facial dysmorphism syndrome
- Intellectual disability, obesity, prognathism, eye and skin anomalies syndrome
- Intellectual disability, seizures, macrocephaly, obesity syndrome
- Lifelong obesity
- Lower body obesity
- Lymphedema associated with obesity
- Mixed conductive AND sensorineural hearing loss
- MOMO syndrome
- Myelopathy due to obesity
- MYT1L-related developmental delay, intellectual disability, obesity syndrome
- Neurological disorder due to obesity
- Neuropathy due to obesity
- Obese
- Obese build
- Obesity
- Obesity associated disorder
- Obesity by adipocyte growth pattern
- Obesity by contributing factors
- Obesity by fat distribution pattern
- Obesity due to leptin receptor gene deficiency
- Obesity in adolescence
- Obesity in mother complicating childbirth
- Obesity monitoring check done
- Obesity monitoring default
- Obesity monitoring deleted
- Obesity monitoring status
- Peripheral neuropathy due to obesity
- PHIP-related behavioral problems, intellectual disability, obesity, dysmorphic features syndrome
- Primary hypomagnesemia, generalized seizures, intellectual disability, obesity syndrome
- Pseudoneoplasm cerebri due to obesity
- Reason for obesity therapy - occupational
- Seen by dietitian
- Sees or has seen dietician
- Severe obesity
- Simple obesity
- Skin striae
- Skin striae due to obesity
- Spastic paraplegia, intellectual disability, nystagmus, obesity syndrome
- Treatment of obesity changed
- Treatment of obesity started
- Type 2 diabetes mellitus in obese
- Understands reducing diet
- X-linked intellectual disability, hypogonadism, ichthyosis, obesity, short stature syndrome
- X-linked sensorineural hearing loss
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to E66.9: its own notes plus those printed at E66 and Chapter 4. A note printed at a category, block or chapter applies to every code under it.
Applicable To
Conditions this code is used for: synonyms of the title or, for "other specified" codes, the conditions assigned to it. The list is not exhaustive.
- Obesity NOS
Excludes1
Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.
Excludes2
Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.
Code First
The underlying condition named in the note is sequenced before this code.
Use Additional Code
Add a second code, after this one, to fully describe the condition.
Notes
General instructions on how these codes are used.
- 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.
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name E66.9, its category, or a range that includes it.
Excludes1 1
These codes carry an Excludes1 note naming E66.9: they are not reported together with it, unless the two conditions are unrelated.
Code First 1
These codes say to code first a condition named in the note, and E66.9 is one of the conditions named.
Use Additional Code 2
These codes say to use an additional code from the note, and E66.9 is one of the codes named.
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
Obesity E66.9
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Obesity
a status with body weight that is grossly above the recommended standards, usually due to accumulation of excess fats in the body. the standards may vary with age, sex, genetic or cultural background. in the body mass index, a bmi greater than 30.0 kg/m2 is considered obese, and a bmi greater than 40.0 kg/m2 is considered morbidly obese (morbid obesity).
Patient EducationClinical
Obesity
Obesity is a disease that means having too much body fat. It is different from being overweight, which means weighing too much. Both terms mean that your weight is greater than what's considered healthy for your height.
The full article covers:
- What is obesity?
- What raises your risk of obesity?
- How is obesity diagnosed?
- What health problems can obesity cause?
- What are the treatments for obesity?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert E66.9 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About E66.9Overview
What is the ICD-10 code for obesity, unspecified?
The ICD-10-CM code for obesity, unspecified is E66.9 (sometimes written as E669). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is E66.9 (Overweight and obesity) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report obesity, unspecified on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does E66.9 group to?
When obesity, unspecified is the principal diagnosis on an inpatient stay, it groups to MS-DRG 641, 640, with relative weights from 0.7864 to 1.3392 depending on complications. Higher weights mean higher Medicare reimbursement.
Does E66.9 justify an inpatient admission?
Not on its own. The Medicare Code Editor lists this code as a questionable admission because obesity, unspecified is not usually sufficient justification for admission to an acute care hospital.
