What is the ICD‑10‑CM code for gastro‑oesophageal reflux disease (GERD)?

ICD-10-CM Code for GERD

The ICD-10-CM code for gastroesophageal reflux disease (GERD) is K21.

Code Structure and Specificity

• K21 is the primary code category for gastroesophageal reflux disease 1, 2
• The code requires a fourth digit to specify the type of GERD:
  • K21.0 – GERD with esophagitis (erosive esophagitis) 1
  • K21.9 – GERD without esophagitis (non-erosive reflux disease/NERD) 1, 3

Clinical Documentation Requirements for Accurate Coding

Document whether esophagitis is present or absent to select between K21.0 and K21.9, as this distinction affects treatment duration and maintenance strategies 4, 1.

• Patients with erosive esophagitis (K21.0) require 8 weeks of PPI therapy and indefinite daily maintenance to prevent recurrence 4, 1
• Patients without esophagitis (K21.9) can be tapered to the lowest effective dose after symptom control 4

Common Documentation Pitfalls

Do not use K21 for functional heartburn or reflux hypersensitivity, as these are distinct diagnoses requiring esophageal physiologic testing (pH-impedance monitoring) to differentiate from true GERD 4, 3.

Ensure the diagnosis is confirmed by either:

• Typical symptoms (heartburn, regurgitation) responding to PPI therapy 4, 1
• Endoscopic evidence of esophagitis 1
• Abnormal esophageal acid exposure on pH monitoring 4, 3

Related Codes to Consider

• K22.1 – Ulcer of esophagus (if severe erosive disease with ulceration is present) 1
• K22.7 – Barrett's esophagus (requires separate coding if documented) 4, 1
• K44 – Diaphragmatic hernia (hiatal hernia, a common anatomic risk factor for GERD) 5, 4