ICD-10 Code E66.813 – Obesity, class 3 (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code E66.813 – Obesity, class 3
What it is
Obesity, class 3 means severe obesity, the highest adult obesity class used in clinical coding. You should use this code when documentation specifically identifies class 3 obesity or an equivalent term.
Clinical signs
Clinical features vary; refer to documentation. Commonly, the record may describe marked excess body weight, high body mass index, or severe obesity noted on exam or problem lists.
When to use this code
Use E66.813 when the provider documents class 3 obesity, severe obesity, or morbid obesity and does not specify a different obesity code. It may appear as a chronic diagnosis on the assessment list or in a visit note. Code it only when the documentation clearly supports the obesity class.
Do not use for
Do not use this code for overweight, unspecified obesity, or obesity classes 1 or 2. Check documentation if the record only says “obese” without a class or severity.
Coding tip
Match the exact obesity term in the provider note, and query if the class is missing or unclear.