2026 ICD-10-CM Diagnosis Code R63.4Abnormal weight loss

ICD-10-CM Codes›R00–R99›R50-R69›R63

ICD-10-CM R63.4
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

R63.4 is a billable ICD-10-CM diagnosis code for abnormal weight loss. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 640 through 641. As a symptom code, it should not be used as a principal diagnosis once a related definitive diagnosis has been established. Coders also document this condition as abnormal intentional weight loss. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other general signs and symptoms.

Code Identity

ICD-10-CM Code
R63.4
Billable Status
Yes — Valid for Submission
Code Describes
Abnormal weight loss
Short Description
Abnormal weight loss
Same as the full description in the CMS dataset.
Parent Code
R63
Symptoms and signs concerning food and fluid intake

Code Classification

ChapterR00–R99Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified
SectionR50-R69General symptoms and signs
CategoryR63Symptoms and signs concerning food and fluid intake
This CodeR63.4Abnormal weight loss

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Abnormal intentional weight loss
  • Abnormal weight loss
  • Abnormal weight loss associated with AIDS
  • Excessive weight loss
  • Intentional weight loss
  • Unexplained weight loss
  • Unintentional weight loss
  • Weight decreased

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

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

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR SYM016
Other general signs and symptoms
Default principal diagnosis: inpatient Yes · outpatient Yes

Convert R63.4 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
783.21 Abnormal loss of weight
Exact Match The mapping is direct, with no qualifiers.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About R63.4Overview

Is R63.4 (Symptoms and signs concerning food and fluid intake) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report abnormal weight loss on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does R63.4 group to?

When abnormal weight loss is the principal diagnosis on an inpatient stay, it groups to MS-DRG 640, 641, with relative weights from 0.7782 to 1.3356 depending on complications. Higher weights mean higher Medicare reimbursement.

Can R63.4 be a principal diagnosis?

Use it with care. This is a symptom code, so once a definitive diagnosis explaining the abnormal weight loss is established, that condition takes the principal position instead.

What is the ICD-9 equivalent of R63.4?

Under the General Equivalence Mappings, abnormal weight loss converts to ICD-9-CM 783.21 (abnormal loss of weight). The mapping is a direct match.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.