Gastro-esophageal reflux disease (K21) ICD-10-CM
The K21 code range covers gastro-esophageal reflux disease with 5 ICD-10-CM diagnosis codes. 3 of them are billable and valid for claim submission in fiscal year 2027, and the category headers group them but cannot themselves be billed.
Type 1 Excludes
A type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.
- newborn esophageal reflux P78.83
Codes in the K21 Range 5 codes · 3 billable
- K21 Gastro-esophageal reflux diseaseNon-billable
- K21.0 Gastro-esophageal reflux disease with esophagitisNon-billable
- K21.00 Gastro-esophageal reflux disease with esophagitis, without bleeding
- K21.01 Gastro-esophageal reflux disease with esophagitis, with bleeding
- K21.9 Gastro-esophageal reflux disease without esophagitis
Clinical Terms in This Code Range
Definitions from the National Library of Medicine for conditions coded in the K21 range.
Gastroesophageal Reflux
Retrograde flow of gastric juice (GASTRIC ACID) and/or duodenal contents (BILE ACIDS; PANCREATIC JUICE) into the distal ESOPHAGUS, commonly due to incompetence of the LOWER ESOPHAGEAL SPHINCTER.
About the K21 Code Range
Gastro-esophageal reflux is the backward flow of stomach juices or contents from the duodenum into the lower esophagus. It is often called acid reflux.
K21 separates reflux disease with esophagitis, or inflammation of the esophagus, from reflux disease without it. K21.0 is further divided into cases without bleeding, K21.00, and cases with bleeding, K21.01. K21.9 identifies reflux disease without esophagitis.
Questions About This Page
How many billable codes are in the K21 range?
Of the 5 codes in this range, 3 are billable and valid for claim submission from October 1, 2026 through September 30, 2027. Category header codes group them but cannot be reported on claims.
What does the K21 range classify?
The range classifies gastro-esophageal reflux disease. Each code links to its own reference page with billing status, MS-DRG grouping, coding notes, and clinical information.
Related References
Source: CMS FY 2027 ICD-10-CM Tabular List and order file, effective October 1, 2026 through September 30, 2027.
