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    OpenPayerBilling CodesDiseases of esophagus, stomach and duodenumICD-10-CM k21-gastro-esophageal-reflux-disease
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    ICD-10-CM Code For Gastro-Esophageal Reflux Disease: Group Overview

    The International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) code group K21 includes diagnoses for gastro-esophageal reflux disease, including reflux esophagitis and other conditions caused by reflux of gastric contents into the esophagus. These ICD-10-CM diagnosis codes are used to document clinical encounters for symptomatic reflux, esophageal inflammation, and related complications, capturing severity and organ involvement. Accurate coding within the ICD-10-CM K21 group supports proper claim adjudication and complete clinical documentation and appropriate reimbursement.

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    ICD-10-CM K21: Gastro-esophageal Reflux Disease Overview

    The International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) code group K21 represents gastro-esophageal reflux disease and related reflux conditions affecting the esophagus and lower esophageal sphincter. These diagnoses target the upper gastrointestinal tract and reflect impairment from reflux of gastric contents causing symptoms or esophageal injury. Accurate coding matters for appropriate clinical documentation and supports correct reimbursement by payers when claims reflect the clinical complexity.

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    When to Use

    Use a code from this group when a patient has clinical evidence of gastro-esophageal reflux disease, such as heartburn with documented reflux or esophageal inflammation attributed to reflux. Codes in this group are also used when documenting complications of reflux that involve the esophagus.

    ICD-10-CM Codes

    3 rows

    ICD-10-CM CodeDescription
    K21.00Gastro-esophageal reflux disease with esophagitis, without bleeding
    K21.01Gastro-esophageal reflux disease with esophagitis, with bleeding
    K21.9Gastro-esophageal reflux disease without esophagitis

    DRG Codes

    5 rows

    DRG CodeDescription
    368Major Esophageal Disorders with MCC
    369Major Esophageal Disorders with CC
    370Major Esophageal Disorders without CC/MCC
    391Esophagitis, Gastroenteritis and Miscellaneous Digestive Disorders with MCC
    392Esophagitis, Gastroenteritis and Miscellaneous Digestive Disorders without MCC

    Typical Clinical Scenarios

    • An adult presents to the primary care clinic with months of daily heartburn, regurgitation of acid into the mouth, and intermittent difficulty swallowing that interfere with sleep and daily activities; symptoms are consistent with chronic reflux without documentation of esophagitis on recent endoscopy, so a non-erosive reflux diagnosis from this group is assigned. Typical codes: K21.9.
    • A patient arrives to the emergency department with sudden-onset severe retrosternal burning and odynophagia; urgent upper endoscopy confirms erosive esophagitis attributable to reflux, and the clinician documents reflux esophagitis as the reason for care, prompting assignment of an esophagitis-with-heartburn code from this group. Typical codes: K21.01, K21.00.
    • A hospitalized elderly patient being treated for chronic respiratory symptoms is found to have aspiration-related cough attributed to recurrent reflux, with documentation that reflux disease is a significant comorbidity complicating management and discharge planning; a reflux diagnosis code from this group is assigned as a comorbid condition affecting care. Typical codes: K21.9.

    Related Codes

    K20-ESOPHAGITIS

    ICD-10-CM Code For Esophagitis: Group Overview

    K22-OTHER-DISEASES-OF-ESOPHAGUS

    ICD-10-CM Code For Other Diseases Of Esophagus: Group Overview

    K23-DISORDERS-OF-ESOPHAGUS

    ICD-10-CM Code For Disorders Of Esophagus In Diseases Classified Elsewhere: Group Overview

    K25-GASTRIC-ULCER

    ICD-10-CM Code For Gastric Ulcer: Group Overview

    K26-DUODENAL-ULCER

    ICD-10-CM Code For Duodenal Ulcer: Group Overview

    K27-PEPTIC-ULCER-SITE-UNSPECIFIED

    ICD-10-CM Code For Peptic Ulcer Site Unspecified: Group Overview

    K28-GASTROJEJUNAL-ULCER

    ICD-10-CM Code For Gastrojejunal Ulcer: Group Overview

    K29-GASTRITIS-AND-DUODENITIS

    ICD-10-CM Code For Gastritis And Duodenitis: Group Overview

    K30-FUNCTIONAL-DYSPEPSIA

    ICD-10-CM Code For Functional Dyspepsia: Group Overview

    Frequently Asked Questions

    References

    1. 1.CPT® Codes and Descriptions. AAPC. Retrieved Aug 11, 2026.Maintains the CPT code set's official descriptions and guidelines, licensed from the American Medical Association, used as the definitional source for CPT codes on this page.
    2. 2.HCPCS Quarterly Update. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's quarterly release of HCPCS Level II codes and short/long descriptors, the source for HCPCS code definitions and update history.
    3. 3.ICD-10-CM Full Code List. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's complete ICD-10-CM diagnosis code list, used to cross-reference diagnosis codes associated with this procedure or service.
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