ICD-10 Code K21 – Gastro-esophageal reflux disease (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code K21 – Gastro-esophageal reflux disease
What it is
K21 identifies gastro-esophageal reflux disease, a condition where stomach contents flow back into the esophagus and cause symptoms or mucosal irritation. Use it when documentation supports chronic reflux disease rather than a brief, isolated episode.
Clinical signs
Typical features include heartburn, acid regurgitation, and chest discomfort related to reflux. Clinical features vary; refer to documentation when notes describe esophagitis, persistent reflux symptoms, or objective evidence supporting GERD.
When to use this code
Use K21 when the provider documents GERD, gastroesophageal reflux disease, or reflux disease as the diagnosis. It may also fit visits for ongoing management of known reflux, follow-up after prior evaluation, or symptoms clearly attributed to GERD in the record.
Do not use for
Do not assign K21 for nonspecific indigestion, isolated nausea, or a single acute reflux complaint without a documented diagnosis. Check documentation if the note instead describes esophagitis, hiatal hernia, or another confirmed cause.
Coding tip
Code only what the provider documents; if GERD is not stated, query or check documentation before assigning K21.