ICD-10 Code K21.0 – Gastro-esophageal reflux disease with esophagitis (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code K21.0 – Gastro-esophageal reflux disease with esophagitis
What it is
K21.0 identifies gastro-esophageal reflux disease when reflux has caused inflammation of the esophagus. Use it when documentation states GERD with esophagitis or reflux esophagitis.
Clinical signs
Typical findings include heartburn, regurgitation, and evidence of esophageal irritation on endoscopy or clinical assessment. Clinical features vary; refer to documentation.
When to use this code
Use K21.0 when the provider documents both GERD and esophagitis, or clearly links esophageal inflammation to reflux. It may also apply when the record states reflux esophagitis. If the note only says GERD without esophagitis, do not choose this code.
Do not use for
Do not use this code for uncomplicated GERD, isolated esophagitis without reflux, or uncertain documentation. Check documentation if the cause of esophagitis is not specified.
Coding tip
Assign K21.0 only when the record supports reflux-related esophagitis, not when GERD is mentioned alone.