ICD-10-CM 2027
ICD-10 code for reflux esophagitis
From the official ICD-10-CM alphabetic index entry “Esophagitis (acute) (alkaline) (chemical) (chronic) (infectional) (necrotic) (peptic) (postoperative) (without bleeding) › reflux”. Page updated September 29, 2026.
About coding reflux esophagitis
The ICD-10-CM code for reflux esophagitis is K21.00 (Gastro-esophageal reflux disease with esophagitis, without bleeding). The official index lists 1 more specific code, so check the documentation for details such as type, cause, site or severity before settling on K21.00.
Within K21.0, choose K21.00 (without bleeding) only when documentation doesn't support a more specific option: with bleeding (K21.01).
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
In MS-DRG v44.0, it is part of the grouping logic for DRG 391 (Esophagitis, Gastroenteritis and Miscellaneous Digestive Disorders with MCC, relative weight 1.2392) and DRG 392 (Esophagitis, Gastroenteritis and Miscellaneous Digestive Disorders without MCC, relative weight 0.7645), in MDC 06 (Diseases and Disorders of the Digestive System), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
More specific reflux esophagitis codes (official index)
- with bleeding K21.01 — Gastro-esophageal reflux disease with esophagitis, with bleeding
Common questions about reflux esophagitis ICD-10 codes
What is the ICD-10 code for reflux esophagitis?
- K21.00 — Gastro-esophageal reflux disease with esophagitis, without bleeding. More specific codes apply when the documentation supports them: K21.01.
Is K21.00 billable?
- Yes. K21.00 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can K21.00 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict K21.00 as a principal diagnosis.
Is K21.00 a CC or MCC?
- No. K21.00 is neither a CC nor an MCC under MS-DRG v44.0.