2026 ICD-10-CM Diagnosis Code K21.9Gastro-esophageal reflux disease without esophagitis

ICD-10-CM Codes›K00–K95›K20-K31›K21

ICD-10-CM K21.9
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

K21.9 is a billable ICD-10-CM diagnosis code for gastro-esophageal reflux disease without esophagitis. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 391 through 392. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Esophageal disorders.

Code Identity

ICD-10-CM Code
K21.9
Billable Status
Yes — Valid for Submission
Code Describes
Gastro-esophageal reflux disease without esophagitis
Short Description
Gastro-esophageal reflux disease without esophagitis
Same as the full description in the CMS dataset.
Parent Code
K21
Gastro-esophageal reflux disease

Code Classification

ChapterK00–K95Diseases of the digestive system
SectionK20-K31Diseases of esophagus, stomach and duodenum
CategoryK21Gastro-esophageal reflux disease
This CodeK21.9Gastro-esophageal reflux disease without esophagitis

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Acid reflux
  • Chalasia of lower esophageal sphincter
  • Diaphragmatic hernia with gastroesophageal reflux disease
  • Digestive system reflux
  • Duodenogastric reflux
  • Erosive gastro-esophageal reflux disease
  • Esophageal reflux finding
  • Excessive gastric reflux
  • Finding of esophageal function
  • Gastric reflux
  • Gastroesophageal reflux disease
  • Gastroesophageal reflux disease in pregnancy
  • Gastroesophageal reflux disease with apnea
  • Gastroesophageal reflux disease without esophagitis
  • Gastroesophageal reflux in child
  • Hiatal hernia with gastroesophageal reflux
  • Laryngitis due to gastroesophageal reflux
  • Laryngopharyngeal reflux
  • Minimal gastric reflux
  • Moderate gastric reflux
  • Non-erosive gastro-esophageal reflux disease
  • Paraesophageal hernia
  • Paraesophageal hernia with gastroesophageal reflux
  • Secondary hernia of abdomen
  • STAG1-related intellectual disability, facial dysmorphism, gastroesophageal reflux syndrome

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • Esophageal reflux NOS

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Allergy, allergic(reaction) (to)
      • milk protein
        • gastroesophageal reflux
    • Cardiochalasia
    • Chalasia(cardiac sphincter)
    • Disease, diseased
      • gastroesophageal reflux (GERD)
    • GERD(gastroesophageal reflux disease)
    • Reflux
    • Reflux
      • acid
    • Reflux
      • esophageal
    • Reflux
      • gastroesophageal
    • Relaxation
      • cardioesophageal

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR DIG004
Esophageal disorders
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Laryngopharyngeal Reflux

    back flow of gastric contents to the laryngopharynx where it comes in contact with tissues of the upper aerodigestive tract. laryngopharyngeal reflux is an extraesophageal manifestation of gastroesophageal reflux.

  • Duodenogastric Reflux

    retrograde flow of duodenal contents (bile acids; pancreatic juice) into the stomach.

Patient EducationClinical

GERD

Your esophagus is the tube that carries food from your mouth to your stomach. Gastroesophageal reflux disease (GERD) happens when a muscle at the end of your esophagus does not close properly. This allows stomach contents to leak back, or reflux, into the esophagus and irritate it.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert K21.9 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
530.81 Esophageal reflux
Exact Match The mapping is direct, with no qualifiers.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About K21.9Overview

Is K21.9 (Gastro-esophageal reflux disease) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report gastro-esophageal reflux disease without esophagitis on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does K21.9 group to?

When gastro-esophageal reflux disease without esophagitis is the principal diagnosis on an inpatient stay, it groups to MS-DRG 391, 392, with relative weights from 0.7796 to 1.2683 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of K21.9?

Under the General Equivalence Mappings, gastro-esophageal reflux disease without esophagitis converts to ICD-9-CM 530.81 (esophageal reflux). The mapping is a direct match.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.