2026 ICD-10-CM Diagnosis Code K21Gastro-esophageal reflux disease

ICD-10-CM Codes›K00–K95›K20-K31›K21

ICD-10-CM K21
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

K21 is a non-billable ICD-10-CM category code for gastro-esophageal reflux disease, so it cannot be submitted on claims. Use a more specific code from this category instead, such as K21.00, K21.01, and K21.9.

Code Identity

ICD-10-CM Code
K21
Billable Status
No — Non-Billable Category
Code Describes
Gastro-esophageal reflux disease
Chapter
K20-K31
Diseases of esophagus, stomach and duodenum

Code Classification

ChapterK00–K95Diseases of the digestive system
SectionK20-K31Diseases of esophagus, stomach and duodenum
CategoryK21Gastro-esophageal reflux disease
This CodeK21Gastro-esophageal reflux disease

Specific Coding for Gastro-esophageal reflux diseaseOverview

Non-specific codes like K21 require more characters. Use one of these billable codes instead:

  • K21.0 for Gastro-esophageal reflux disease with esophagitis

  • Use K21.00 for Gastro-esophageal reflux disease with esophagitis, without bleeding

  • Use K21.01 for Gastro-esophageal reflux disease with esophagitis, with bleeding

  • Use K21.9 for Gastro-esophageal reflux disease without esophagitis

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Type 1 Excludes

  • newborn esophageal reflux P78.83

Patient EducationClinical

GERD

Your esophagus is the tube that carries food from your mouth to your stomach. Gastroesophageal reflux disease (GERD) happens when a muscle at the end of your esophagus does not close properly. This allows stomach contents to leak back, or reflux, into the esophagus and irritate it.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

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 K21Overview

Is K21 (Gastro-esophageal reflux disease) a billable code?

No. This is a category header that groups the codes for gastro-esophageal reflux disease, and headers cannot be submitted on claims. Claims for gastro-esophageal reflux disease need a more specific code from this category, such as K21.00, K21.01, and K21.9.