What is the ICD-10-CM code for abnormal weight loss?

The primary ICD-10-CM code for abnormal weight loss is R63.4 (Abnormal weight loss). There are 9 billable abnormal weight loss codes in FY2027, covering different types and underlying causes.

How many ICD-10-CM codes are there for abnormal weight loss?

There are 9 ICD-10-CM codes for abnormal weight loss in the FY2027 tabular list, of which 9 are billable. These codes fall under Chapter 18 of the ICD-10-CM classification.

Which chapter covers abnormal weight loss in ICD-10-CM?

Weight Loss codes are classified in Chapter 18 of the ICD-10-CM tabular list: R00–R99 (Symptoms, Signs and Abnormal Clinical and Laboratory Findings).

Weight Loss ICD-10-CM codes

ICD-10-CM codes for abnormal or unintentional weight loss, underweight, and cachexia, with related codes for malnutrition and low BMI.

9 codes, 9 billable. FY2027, valid from October 1, 2026. In chapter 18: Symptoms, Signs and Abnormal Clinical and Laboratory Findings.

How to code Weight Loss

R63.4 is abnormal weight loss, used for unintentional or unexplained weight loss. R63.6 is underweight, and R64 is cachexia (wasting). Cachexia due to an underlying condition, such as cancer, is coded with the underlying condition first. Loss of appetite is R63.0 and adult failure to thrive is R62.7.

When the provider diagnoses malnutrition, code it from E40-E46 instead of relying on R63.4 alone, for example E44.0 for moderate and E43 for severe protein-calorie malnutrition. See the malnutrition guide for the full set.

BMI codes are reported in addition when the BMI is documented and an associated diagnosis such as underweight is present. For adults, Z68.18 is BMI 18.4 or less and Z68.19 is BMI 18.5-19.9. BMI can be taken from dietitian or other clinician notes, but the weight diagnosis must come from the provider.

All Weight Loss codes

More Symptom and Finding Guides

Chest Pain Abdominal Pain Shortness of Breath and Dyspnea Fever Fatigue and Malaise Dizziness and Syncope Nausea and Vomiting Cough Headache Elevated Blood Pressure Reading Elevated Blood Glucose and Prediabetes Hematuria All 335 guides