R63.4 Abnormal weight loss

Billable ICD-10-CM code, FY2026.

Applies from R63 Symptoms and signs concerning food and fluid intake

Excludes1 (never code together)

• bulimia NOS (F50.2-)

MS-DRG index

Defines the logic of DRG(s) 640-641 in MDC 10.

Approximate ICD-9-CM (GEMs)

• 783.21 Loss of weight

Code annotations containing back-references to R63.4

Back-references to R63.4

• Type 1 Excludes: R63.6 Underweight ("abnormal weight loss (R63.4)")
• Type 1 Excludes: R64 Cachexia ("abnormal weight loss (R63.4)")
• Use Additional: U07.0 Vaping-related disorder ("weight loss (R63.4)")

Diagnosis Index entries for R63.4

• Abnormal, abnormality, abnormalities › loss of › weight
• Excess, excessive, excessively › weight › loss
• Loss (of) › weight (abnormal) (cause unknown)
• Weight › loss (abnormal) (cause unknown)

Nearby codes

• R63.3 Feeding difficulties
• R63.30 Feeding difficulties, unspecified
• R63.31 Pediatric feeding disorder, acute
• R63.32 Pediatric feeding disorder, chronic
• R63.39 Other feeding difficulties
• R63.4 Abnormal weight loss (this code)
• R63.5 Abnormal weight gain
• R63.6 Underweight
• R63.8 Other symptoms and signs concerning food and fluid intake