K21.9Gastro-esophageal reflux disease without esophagitis

K21.9 is the ICD-10-CM diagnosis code for Gastro-esophageal reflux disease without esophagitis. It belongs to category K21 (Gastro-esophageal reflux disease), block K20-K31 (diseases of esophagus, stomach and duodenum) and chapter 11 (diseases of the digestive system). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

Within K21, choose K21.9 (without esophagitis) only when documentation doesn't support a more specific option: with esophagitis (K21.0).

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.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Before ICD-10, this condition was coded in ICD-9-CM as 530.81 (esophageal reflux).