K21.9 Gastro-esophageal reflux disease without esophagitis

The ICD-10-CM code for Gastro-esophageal reflux disease without esophagitis is K21.9 (FY2026). It is a billable, claim-ready diagnosis code.

Choosing between codes? See the guide: ICD-10 code for GERD (acid reflux).

Classification

Chapter

11: Diseases of the digestive system (K00-K95)

Section

K20-K31: Diseases of esophagus, stomach and duodenum (K20-K31)

Category K21

5 codes (3 billable)

FY2026 Status

Stable since FY2024

Also Known As

ICD-10-CM Alphabetic Index entries that lead to K21.9:

• GERD (gastroesophageal reflux disease)
• Reflux
• Chalasia (cardiac sphincter)
• Cardiochalasia
• Disease, diseased › gastroesophageal reflux (GERD)
• Reflux › gastroesophageal
• Reflux › acid
• Reflux › esophageal

Inclusion Terms

• Esophageal reflux NOS

U.S. Hospital Utilization

• An estimated 5,517,786 U.S. inpatient stays in 2023 included K21.9 among the documented diagnoses.
• 17,860 stays listed it as the principal diagnosis.

Source: National Inpatient Sample (NIS), Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality, 2016–2023. National survey-weighted estimates.

Prevalence & Statistics

• Researchers estimate that about 20 percent of people in the United States have GERD (gastroesophageal reflux disease). (NIDDK - Definition & Facts for GER & GERD (Adults), 2020)

Official Coding Guidelines

Chapter 11 reserved for future expansion

11. Chapter 11: Diseases of the Digestive System (K00-K95) Reserved for future guideline expansion

Source: CMS — ICD-10-CM Official Guidelines for Coding and Reporting, FY2026

References

• CMS — ICD-10-CM Official Code Set and Guidelines, FY2026
• CDC/NCHS — ICD-10-CM Files and Browser Tool
• AHRQ — HCUP National Inpatient Sample, Frequencies by Diagnosis Code (2016–2023)
• NIDDK - Definition & Facts for GER & GERD (Adults) (2020)