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ICD-10 Code K21.9: Gastro-esophageal reflux disease without esophagitis

K21.9 is a billable ICD-10 diagnosis code used to classify Gastro-esophageal reflux disease without esophagitis in medical records and claims. You may see this code in hospital records, discharge summaries, insurance claims, encounter documentation, referrals, or other healthcare billing and coding records. ICD-10 codes are diagnosis classification codes used in healthcare records, reporting, coding workflows, and billing support. This code sits within the broader ICD-10 area for Diseases of the digestive system (K00-K95).

Reviewed by HealthAssure Clinical TeamUpdated 26 May 2026

What is this code?

ICD-10 codes are diagnosis classification codes used in healthcare records, reporting, coding workflows, and billing support. This code sits within the broader ICD-10 area for Diseases of the digestive system (K00-K95).

When is it used?

  • May be used when a clinician documents gastro-esophageal reflux disease without esophagitis in a patient's medical record.
  • May appear in hospital records, claims, referrals, and clinical documentation.
  • This code can be used as a clinically usable diagnosis entry in standardized coding workflows.

What it does not mean

  • A code alone does not explain severity, treatment plan, or outcome.
  • A medical code should not be treated as a substitute for a doctor's diagnosis or advice.

Code hierarchy

chapter
11Diseases of the digestive system (K00-K95)
block
K20-K31Diseases of esophagus, stomach and duodenum
category
K21Gastro-esophageal reflux disease
currentK21

Official coding notes

Inclusion terms
  • Esophageal reflux NOS

Where you may see this code

You may see this code in hospital records, discharge summaries, insurance claims, encounter documentation, referrals, or other healthcare billing and coding records.

Related specialists

GastroenterologistGeneral Physician

Coverage-related procedures and services

CPT 81418high
DRUG METABOLISM (EG, PHARMACOGENOMICS) GENOMIC SEQUENCE ANALYSIS PANEL, MUST INCLUDE TESTING OF AT LEAST 6 GENES, INCLUDING CYP2C19, CYP2D6, AND CYP2D6 DUPLICATION/DELETION ANALYSIS
Source: CMS coverage guidance
CPT 0349Uhigh
DRUG METABOLISM OR PROCESSING (MULTIPLE CONDITIONS), WHOLE BLOOD OR BUCCAL SPECIMEN, DNA ANALYSIS, 27 GENE REPORT, WITH VARIANT ANALYSIS, INCLUDING REPORTED PHENOTYPES AND IMPACTED GENE-DRUG INTERACTIONS
Source: CMS coverage guidance
CPT 0423Uhigh
PSYCHIATRY (EG, DEPRESSION, ANXIETY), GENOMIC ANALYSIS PANEL, INCLUDING VARIANT ANALYSIS OF 26 GENES, BUCCAL SWAB, REPORT INCLUDING METABOLIZER STATUS AND RISK OF DRUG TOXICITY BY CONDITION
Source: CMS coverage guidance
CPT 81225high
CYP2C19 (CYTOCHROME P450, FAMILY 2, SUBFAMILY C, POLYPEPTIDE 19) (EG, DRUG METABOLISM), GENE ANALYSIS, COMMON VARIANTS (EG, *2, *3, *4, *8, *17)
Source: CMS coverage guidance
CPT 81226high
CYP2D6 (CYTOCHROME P450, FAMILY 2, SUBFAMILY D, POLYPEPTIDE 6) (EG, DRUG METABOLISM), GENE ANALYSIS, COMMON VARIANTS (EG, *2, *3, *4, *5, *6, *9, *10, *17, *19, *29, *35, *41, *1XN, *2XN, *4XN)
Source: CMS coverage guidance
CPT 43235high
ESOPHAGOGASTRODUODENOSCOPY, FLEXIBLE, TRANSORAL; DIAGNOSTIC, INCLUDING COLLECTION OF SPECIMEN(S) BY BRUSHING OR WASHING, WHEN PERFORMED (SEPARATE PROCEDURE)
Source: CMS coverage guidance

Coding guidelines

Compatibility

Legacy and official ICD code match exactly.
Legacy codes
K21.9

Common synonyms

Gastro-esophageal reflux disease without esophagitis

Frequently asked questions

Code details

CodeK21.9
SystemICD10
Display nameGastro-esophageal reflux disease without esophagitis
ChapterDiseases of the digestive system (K00-K95)
BlockDiseases of esophagus, stomach and duodenum

Flags

BillableYes
Valid clinical useYes

Source

SourceICD-10
Version2026-annual
Releaseannual
Year2026

Index terms

Matched terms
Allergy, allergic(reaction) (to)CardiochalasiaChalasia(cardiac sphincter)Disease, diseasedGERD(gastroesophageal reflux disease)RefluxRefluxRefluxRefluxRelaxation
See also
Reaction, adverse, foodDisease, gastroesophageal reflux

About this content

This page is prepared by HealthAssure's clinical team using official coding standards from ICD-10. AI tools assist with drafting explanations, which are then reviewed and verified by healthcare professionals for accuracy. This content is for informational purposes and does not replace professional medical advice. Meet our team.

ICD-10 Code K21.9 for Gastro-esophageal reflux disease without esophagitis | HealthAssure