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  6. 2025 ICD-10-CM Code E66.9

2025 ICD-10-CM Diagnosis Code E66.9

Obesity, unspecified

ICD-10-CM Code:
E66.9
ICD-10 Code for:
Obesity, unspecified
Is Billable?
Yes - Valid for Submission
Chronic Condition Indicator: [1]
Chronic
Code Navigator:

E66.9 is a billable diagnosis code used to specify a medical diagnosis of obesity, unspecified. The code is valid during the current fiscal year for the submission of HIPAA-covered transactions from October 01, 2024 through September 30, 2025.

This code is not usually sufficient justification for admission to an acute care hospital when used as a principal diagnosis.

Unspecified diagnosis codes like E66.9 are acceptable when clinical information is unknown or not available about a particular condition. Although a more specific code is preferable, unspecified codes should be used when such codes most accurately reflect what is known about a patient's condition. Specific diagnosis codes should not be used if not supported by the patient's medical record.

Code Classification

  • Endocrine, nutritional and metabolic diseases
    E00–E89
    • Overweight, obesity and other hyperalimentation
      E65-E68
      • Overweight and obesity
        E66

Approximate Synonyms

The following list of clinical terms are approximate synonyms, alternative descriptions, or common phrases that might be used by patients, healthcare providers, or medical coders to describe the same condition. These synonyms and related diagnosis terms are often used when searching for an ICD-10 code, especially when the exact medical terminology is unclear. Whether you're looking for lay terms, similar diagnosis names, or common language alternatives, this list can help guide you to the correct ICD-10 classification.

  • Autosomal dominant complex hereditary spastic paraplegia
  • Benign intracranial hypertension
  • Body mass index 30+ - obesity
  • Central obesity
  • Childhood 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
  • Has seen dietitian - obesity
  • 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
  • Neurological disorder due to obesity
  • Neurological disorder due to obesity
  • Neurological disorder due to obesity
  • Neurological disorder due to obesity
  • Neuropathy due to obesity
  • Obese
  • Obese build
  • Obese class I
  • Obese class II
  • 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
  • Obesity monitoring status
  • Obesity monitoring status
  • Obesity monitoring status
  • Obesity monitoring status
  • Obesity monitoring status
  • Obesity monitoring status
  • Peripheral neuropathy due to obesity
  • PHIP-related behavioral problems, intellectual disability, obesity, dysmorphic features 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

Clinical Classification

Clinical Classifications group individual ICD-10-CM diagnosis codes into broader, clinically meaningful categories. These categories help simplify complex data by organizing related conditions under common clinical themes.

They are especially useful for data analysis, reporting, and clinical decision-making. Even when diagnosis codes differ, similar conditions can be grouped together based on their clinical relevance. Each category is assigned a unique CCSR code that represents a specific clinical concept, often tied to a body system or medical specialty.

Obesity

CCSR Code: END009

Inpatient Default: Y - Yes, default inpatient assignment for principal diagnosis or first-listed diagnosis.

Outpatient Default: Y - Yes, default outpatient assignment for principal diagnosis or first-listed diagnosis.

Clinical Information

  • Diabesity

    co-occurrence of diabetes mellitus and obesity largely due to diabetic complication from hyperglycemia. diabesity is also associated with faster deterioration of diabetic symptoms and complications.

  • 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).

  • Obesity Hypoventilation Syndrome

    hypoventilation syndrome in very obese persons with excessive adipose tissue around the abdomen and diaphragm. it is characterized by diminished to absent ventilatory chemoresponsiveness; chronic hypoxia; hypercapnia; polycythemia; and long periods of sleep during day and night (hypersomnolence). it is a condition often related to obstructive sleep apnea but can occur separately.

  • Obesity Management

    an integrated professional approach to screening, evaluation, control, and reduction of abnormal weight gain.

  • Obesity Paradox

    an observation that high body mass index is sometimes associated with lower cardiovascular disease mortality in certain population, e.g., elderly.

  • Obesity, Abdominal

    a condition of having excess fat in the abdomen. abdominal obesity is typically defined as waist circumferences of 40 inches or more in men and 35 inches or more in women. abdominal obesity raises the risk of developing disorders, such as diabetes; hypertension; and metabolic syndrome.

  • Obesity, Metabolically Benign

    a sub-phenotype of obese individuals who have a risk for cardiovascular diseases between that of healthy individuals with normal weight and unhealthy individuals with obesity.

  • Obesity, Morbid

    the condition of weighing two, three, or more times the ideal weight, so called because it is associated with many serious and life-threatening disorders. in the body mass index, morbid obesity is defined as having a bmi greater than 40.0 kg/m2.

  • Pediatric Obesity

    body mass index in children (ages 2-12) and in adolescents (ages 13-18) that is grossly above the recommended cut-off for a specific age and sex. for infants less than 2 years of age, obesity is determined based on standard weight-for-length percentile measures.

  • Pregnancy in Obesity

    body mass index in pregnant people that is excessively above the recommended cut-off.

  • Weight Prejudice

    negative attitudes towards and beliefs about others because of their weight. these negative attitudes are manifested by stereotypes and/or prejudice towards people with weight over or under a cultural norm.

  • Choroideremia

    an x chromosome-linked abnormality characterized by atrophy of the choroid and degeneration of the retinal pigment epithelium causing night blindness.

  • Weight Gain

    increase in body weight over existing weight.

  • Body Mass Index

    an indicator of body density as determined by the relationship of body weight to body height. bmi=weight (kg)/height squared (m2). bmi correlates with body fat (adipose tissue). their relationship varies with age and gender. for adults, bmi falls into these categories: below 18.5 (underweight); 18.5-24.9 (normal); 25.0-29.9 (overweight); 30.0 and above (obese). (national center for health statistics, centers for disease control and prevention)

Tabular List of Diseases and Injuries

The following annotation back-references are applicable to this diagnosis code. The Tabular List of Diseases and Injuries is a list of ICD-10-CM codes, organized "head to toe" into chapters and sections with coding notes and guidance for inclusions, exclusions, descriptions and more.


Inclusion Terms

Inclusion Terms
These terms are the conditions for which that code is to be used. The terms may be synonyms of the code title, or, in the case of "other specified" codes, the terms are a list of the various conditions assigned to that code. The inclusion terms are not necessarily exhaustive. Additional terms found only in the Alphabetic Index may also be assigned to a code.
  • Obesity NOS

Index to Diseases and Injuries References

The following annotation back-references for this diagnosis code are found in the injuries and diseases index. The Index to Diseases and Injuries is an alphabetical listing of medical terms, with each term mapped to one or more ICD-10-CM code(s).

Code Edits

The Medicare Code Editor (MCE) detects errors and inconsistencies in ICD-10-CM diagnosis coding that can affect Medicare claim validity. These Medicare code edits help medical coders and billing professionals determine when a diagnosis code is not appropriate as a principal diagnosis, does not meet coverage criteria. Use this list to verify whether a code is valid for Medicare billing and to avoid claim rejections or denials due to diagnosis coding issues.

Questionable admission codes

Some diagnoses are not usually sufficient justification for admission to an acute care hospital. For example, if a patient is given code R030 for elevated blood pressure reading, without diagnosis of hypertension, then the patient would have a questionable admission, since elevated blood pressure reading is not normally sufficient justification for admission to a hospital. The following list contains diagnosis codes identified as questionable admission when used.

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Convert E66.9 to ICD-9-CM

Below are the ICD-9 codes that most closely match this ICD-10 code, based on the General Equivalence Mappings (GEMs). This ICD-10 to ICD-9 crosswalk tool is helpful for coders who need to reference legacy diagnosis codes for audits, historical claims, or approximate code comparisons.

Obesity NOS

ICD-9-CM: 278.00

Approximate Flag - The approximate mapping means this ICD-10 code does not have an exact ICD-9 equivalent. The matched code is the closest available option, but it may not fully capture the original diagnosis or clinical intent.

View Conversion

Patient Education


Obesity

Obesity means having too much body fat. It is different from being overweight, which means weighing too much. The weight may come from muscle, bone, fat, and/or body water. Both terms mean that a person's weight is greater than what's considered healthy for his or her height.

Obesity happens over time when you eat more calories than you use. The balance between calories-in and calories-out differs for each person. Factors that might affect your weight include your genetic makeup, overeating, eating high-fat foods, and not being physically active.

Obesity increases your risk of diabetes, heart disease, stroke, arthritis, and some cancers. If you have obesity, losing even 5 to 10% of your weight can delay or prevent some of these diseases. For example, that means losing 10 to 20 pounds if you weigh 200 pounds.

NIH: National Institute of Diabetes and Digestive and Kidney Diseases


[Learn More in MedlinePlus]

Take Charge of Your Health: A Guide for Teenagers

Provides small, achievable steps to help teenagers make healthier food choices, be more active, and get enough sleep.
[Learn More in MedlinePlus]

Code History

  • FY 2024 - No Change, effective from 10/1/2023 through 9/30/2024
  • FY 2023 - No Change, effective from 10/1/2022 through 9/30/2023
  • FY 2022 - No Change, effective from 10/1/2021 through 9/30/2022
  • FY 2021 - No Change, effective from 10/1/2020 through 9/30/2021
  • FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020
  • FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
  • FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018
  • FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
  • FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016. This was the first year ICD-10-CM was implemented into the HIPAA code set.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.