ICD-10-CM · Digestive system
ICD-10-CM · Digestive systemK21.9: Gastro-esophageal reflux disease without esophagitis
K21.9 is the ICD-10-CM code for Gastro-esophageal reflux disease without esophagitis. Billable on U.S. claims with supporting documentation. Chapter: Digestive system. Category: K21.
About this code
Gastro-esophageal reflux disease without esophagitis.
K21.9 is an ICD-10-CM diagnosis code for gastro-esophageal reflux disease without esophagitis. It sits in the 11. Digestive system chapter of the U.S. clinical modification, under category K21.
This code is billable on U.S. healthcare claims when supported by appropriate clinical documentation. The patient chart must establish the diagnosis, capture any clinical detail encoded in the code (severity, laterality, encounter type, complications where applicable), and demonstrate medical necessity for the billed services.
Payer-specific coverage rules vary. Always cross-check against the current Local Coverage Determinations (LCDs) and National Coverage Determinations (NCDs) for the payer adjudicating the claim, plus any specialty-specific CMS Medicare Administrative Contractor guidance.
Billing context
What practitioners watch for on K21.9.
Code-specific billing guidance for K21.9, written from production billing experience.
Documentation
GERD without esophagitis. If esophagitis is documented (erosive K21.0, non-erosive K21.00, with bleeding K21.01), use the more specific code. Pair with K22.7 if Barrett esophagus is documented.
Common denial categories
- CO-16: Information missing or incorrect on the claim or in supporting documentation. Add documentation specificity that supports the coded detail; resubmit with corrected information.
- CO-50: Service not deemed medically necessary by the payer. Confirm the diagnosis-procedure relationship matches LCD/NCD coverage, attach clinical justification, appeal with documentation.
- CO-11: Diagnosis is inconsistent with the procedure performed. Verify the diagnosis-to-procedure pairing per payer policy; correct the linked diagnosis pointer or the procedure code.
Coverage signal
PPI prescriptions are typically covered without prior auth. Endoscopy for chronic GERD generally requires documented refractory symptoms or alarm features per payer policy.
Common specialties
Gastroenterology · Family Medicine · Internal Medicine
Companion CPT codes
Procedures commonly billed alongside K21.9 based on Medonix client production data and CMS coding guidance.
- 45378Diagnostic colonoscopy
- G0121Screening colonoscopy, average risk
- 43239Upper GI endoscopy with biopsy
- 99214Office visit, established, moderate complexity
CPT is a registered trademark of the American Medical Association. Codes shown for educational reference only.
Sources
Where this entry comes from.
- NLM Clinical Tables Search Service: the official U.S. National Library of Medicine API for ICD-10-CM lookup.
- CDC National Center for Health Statistics: annual ICD-10-CM Tabular List release with effective date October 1.
- CMS Medicare Coverage Database: Local Coverage Determinations and National Coverage Determinations for payer-specific rules.
Frequently asked
About ICD-10 code K21.9.
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