R63.6
BillableUnderweight
Underweight
Coding Notes
Excludes 1
Codes that cannot be used together with this code (mutual exclusion)
Excludes 2
Conditions not included here, but the patient may have both
- •abnormal findings on antenatal screening of motherO28
- •certain conditions originating in the perinatal periodP04-P96
- signs and symptoms classified in the body system chapters
- •signs and symptoms of breast,N63, N64.5
Use Additional Code
Additional codes that should follow this code
Related Codes(7)
ICD-11 Equivalents(1)
ICD-11 Equivalents
View full mappingCorresponding ICD-11 codes from the WHO crosswalk mapping
Also Known As / Clinical Terms(67)
SNOMED CT
- AN - Anorexia nervosa56882008
- Anorexia nervosa56882008
- Skinny build61294007
- Thin build61294007
- Anorexia nervosa, binge-eating purging type63393005
- Anorexia nervosa, restricting subtype77675002
- Anorexia nervosa, restricting type77675002
- Low body weight248342006
- Underweight248342006
- Mild thinness in adulthood717931007
- Moderate thinness in adulthood717932000
- Severe thinness in adulthood717933005
- Anorexia nervosa co-occurrent with dangerously low body weight722959000
- Anorexia nervosa co-occurrent with significantly low body weight722960005
- Anorexia nervosa of restricting type with dangerously low body weight723917005
- Dangerously low body weight co-occurrent and due to anorexia nervosa of restricting type723917005
- Anorexia nervosa, binge-eating purging type with dangerously low body weight723918000
- Dangerously low body weight co-occurrent and due to anorexia nervosa of binge-eating purging type723918000
- Anorexia nervosa, restricting type with significantly low body weight723919008
- Significantly low body weight co-occurrent and due to anorexia nervosa of restricting type723919008
- Anorexia nervosa of binge-eating purging type with significantly low body weight723920002
- Significantly low body weight co-occurrent and due to anorexia nervosa of binge-eating purging type723920002
- Thin build in adult735540007
- Underweight in infancy762490009
- Underweight in childhood762491008
- Underweight in adolescence762492001
UMLS
Clinical Terms
- Underweight in childhood
- Underweight (finding)
- Anorexia nervosa
- Anorexia nervosa, restricting type
- Severe thinness in adulthood
- weight loss severe
- Anorexia nervosa, restricting subtype
- Anorexia nervosa, restricting type with significantly low body weight
- Underweight in adolescence
- Anorexia nervosa, binge-eating purging type
- AN - Anorexia nervosa
- Anorexia nervosa co-occurrent with significantly low body weight
- Low weight
- Dangerously low body weight co-occurrent and due to anorexia nervosa of binge-eating purging type
- Thin build in adult
- Significantly low body weight co-occurrent and due to anorexia nervosa of binge-eating purging type
- Low body weight
- Anorexia nervosa of restricting type with dangerously low body weight
- severe weight loss
- weight low
- patient underweight
- Thin build
- Underweight in infancy
- Significantly low body weight co-occurrent and due to anorexia nervosa of restricting type
- Skinny build
- Anorexia nervosa of binge-eating purging type with significantly low body weight
- Dangerously low body weight co-occurrent and due to anorexia nervosa of restricting type
- Mild thinness in adulthood
- Moderate thinness in adulthood
- Anorexia nervosa, binge-eating purging type with dangerously low body weight
- Anorexia nervosa co-occurrent with dangerously low body weight
Frequently Asked Questions
What is the ICD-10 code for underweight?
The ICD-10-CM code for underweight is R63.6. The full clinical description is "Underweight". R63.6 is a billable/specific code that can be used on insurance claims and medical billing.
What does ICD-10 code R63.6 mean?
ICD-10-CM code R63.6 represents “Underweight”. It is classified under Chapter 18: Symptoms, Signs and Abnormal Clinical and Laboratory Findings and is a billable/specific code that can be used on a claim.
Is R63.6 a billable code?
Yes, R63.6 is a billable/specific ICD-10-CM code and can be used to indicate a diagnosis on a medical claim.
What chapter is R63.6 in?
R63.6 is in Chapter 18: Symptoms, Signs and Abnormal Clinical and Laboratory Findings (codes R00-R99).
What codes cannot be used with R63.6?
R63.6 has Excludes1 notes indicating codes that cannot be used together with it, including: bulimia NOS (F50.2-); abnormal weight loss (R63.4); anorexia nervosa (F50.0-); and 1 more.
Are additional codes required with R63.6?
Yes, when using R63.6, also report: body mass index (BMI), if known (Z68.-).
What SNOMED CT codes does R63.6 map to?
R63.6 maps to 18 SNOMED CT concepts: 56882008, 722959000, 722960005, 723920002, 723917005, and 13 more. SNOMED CT is a clinical terminology used in electronic health records.
What are the UMLS CUIs for R63.6?
R63.6 is linked to 1 UMLS Concept Unique Identifier: C0041667. The UMLS (Unified Medical Language System) integrates multiple biomedical vocabularies maintained by the U.S. National Library of Medicine.
How does R63.6 relate to ICF functioning codes?
ICF (International Classification of Functioning, Disability and Health) codes describe how conditions like underweight affect a person's functioning — body functions, activities, participation, and environmental factors. AutoICD provides ICF Core Sets for 12+ conditions and can map clinical text to ICF categories automatically. Browse the ICF directory to explore functioning codes.
What is the ICD-11 equivalent of R63.6?
R63.6 maps to the ICD-11 code: MG43.4Z (Insufficient intake of food or water due to self neglect, unspecified).
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Includes SNOMED Clinical Terms® (SNOMED CT®) used by permission of SNOMED International. Includes content from the UMLS Metathesaurus, courtesy of the U.S. National Library of Medicine.