All ICD10 Codes

K21

Non-Billable
ChapterK00–K95
Rankcategory
Official Description

Gastro-esophageal reflux disease

Metadata & Insights
  • •2026 ICD-10-CM Edition - Effective October 1, 2025.
  • •Non-billable category (requires more specific sub-code).
  • •Chapter 11: Diseases of the Digestive System (K00-K95).

CH11 Parent Instructions

Excludes2(Not included here)
  • certain conditions originating in the perinatal period (P04-P96)
  • certain infectious and parasitic diseases (A00-B99)
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)
  • congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)
  • endocrine, nutritional and metabolic diseases (E00-E88)
  • injury, poisoning and certain other consequences of external causes (S00-T88)
  • neoplasms (C00-D49)
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)

K20-K31 Parent Instructions

Excludes2(Not included here)
  • hiatus hernia (K44.-)

Instructional Notes

Excludes1(Not coded here)
  • newborn esophageal reflux (P78.83)

Clinical Hierarchy

CH11Diseases of the digestive system (K00-K95)
K20-K31Diseases of esophagus, stomach and duodenum (K20-K31)
K21Gastro-esophageal reflux disease
K21.0Gastro-esophageal reflux disease with esophagitis
K21.9Gastro-esophageal reflux disease without esophagitis

Applicable Ancestor Context

The following parent sections contain instructions or notes that apply to K21:

blockK20-K31
Diseases of esophagus, stomach and duodenum (K20-K31)
View context instructions
chapterCH11
Diseases of the digestive system (K00-K95)
View context instructions

Alphabetic Index Mentions

These are Diagnosis Index lookup paths that route to K21. Use them as entry terms for search, then confirm final coding instructions in the Tabular List and notes above.

24 raw paths
Allergy, allergic (reaction) (to)3 unique routes
milk protein(3 variants)
gastroesophageal reflux→K21(3 variants)
with esophagitis (without bleeding)→K21(2 variants)
with bleeding→K21
Cardiochalasia1 unique routes
Direct index entry→K21
Chalasia (cardiac sphincter)1 unique routes
Direct index entry→K21
Disease, diseased3 unique routes
gastroesophageal reflux (GERD)→K21(3 variants)
with esophagitis (without bleeding)→K21(2 variants)
with bleeding→K21
Esophagitis (acute) (alkaline) (chemical) (chronic) (infectional) (necrotic) (peptic) (postoperative) (without bleeding)4 unique routes
due to gastrointestinal reflux disease (without bleeding)→K21(2 variants)
with bleeding→K21
reflux→K21(2 variants)
with bleeding→K21
GERD (gastroesophageal reflux disease)1 unique routes
Direct index entry→K21
Reflux8 unique routes
Direct index entry→K21
acid→K21
esophageal→K21(3 variants)
with esophagitis (without bleeding)→K21(2 variants)
with bleeding→K21
gastroesophageal→K21(3 variants)
with esophagitis (without bleeding)→K21(2 variants)
with bleeding→K21
Relaxation1 unique routes
cardioesophageal→K21
Ulcer, ulcerated, ulcerating, ulceration, ulcerative2 unique routes
esophagus (peptic)(2 variants)
due to(2 variants)
gastrointestinal reflux disease (without bleeding)→K21(2 variants)
with bleeding→K21

MS-DRG Classification

2026

No direct MS-DRG triggers identified.

Cross Reference

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