E66

E66 is a designation used in the ICD-10-CM coding system to classify obesity and related nutritional disorders. It forms a code block that includes several subcategories intended to specify the etiology or presentation of obesity, such as E66.0 Obesity due to excess calories and E66.9 Obesity, unspecified. These codes are used by clinicians, medical coders, and insurers to document obesity for clinical care, billing, and epidemiological purposes.

The E66 category covers obesity resulting from caloric excess as well as other conditions that contribute to obesity or its clinical profile. The exact subcodes and their definitions are provided in the ICD-10-CM reference materials and are updated periodically, so current coding manuals should be consulted for precise usage. In practice, an obesity diagnosis may be assigned when documented by a clinician, and it is commonly used alongside codes that describe related comorbidities such as metabolic or cardiovascular conditions.

Obesity is a chronic condition characterized by excess body fat and is associated with increased health risks, including diabetes, cardiovascular disease, and joint disorders. Coding with E66 supports treatment planning, resource allocation, and research, and it is frequently used in conjunction with other codes that describe obesity-related complications. The ICD-10-CM system also includes related Z codes used to document BMI and other obesity-related factors as relevant to the patient’s records. Coding practices may vary by payer and jurisdiction, so current guidelines should be consulted.