R63.6

Billable

Underweight

R63.6 is the ICD-10-CM code for Underweight. It is a billable, specific code valid for reimbursement.

Status
Billable
Chapter
R00-R99
Parent
R63
Edition
FY2026

R00-R99 Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified

What this means — in plain language

MedlinePlus · NIH

What is body weight? Body weight is the total mass of your body. Keeping track of your weight is one way to check for changes in your health, but it can't tell you the whole story. That's because your weight includes muscle, bone, fat, and water. Also, everyday factors can play a role in your weight, such as your: Diet Activity level Stress level Sleep habits Family history and genetics Age What factors help…

Read more about Body Weight at MedlinePlus ↗

Source: U.S. National Library of Medicine (MedlinePlus). Informational only — not medical advice.

Excludes1 — not coded here

  • abnormal weight loss (R63.4)
  • anorexia nervosa (F50.0-)
  • malnutrition (E40-E46)

Use additional code

  • code to identify body mass index (BMI), if known (Z68.-)

Frequently asked questions

What is ICD-10 code R63.6?
R63.6 is the ICD-10-CM code for "Underweight". It falls under R00-R99 Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified.
Is R63.6 a billable code?
Yes — R63.6 is a billable, specific ICD-10-CM code valid for reimbursement.
What is excluded from R63.6?
Excludes1 (not coded here): abnormal weight loss (R63.4); anorexia nervosa (F50.0-); malnutrition (E40-E46).

Source: CMS ICD-10-CM FY2026. For informational purposes only — not medical advice. See our medical disclaimer.

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