K21 – Gastro-esophageal reflux disease
ICD-10-CM 2027 diagnosis code · Diseases of esophagus, stomach and duodenum
ICD-10-CM code
K21
- Code
K21(claims format:K21)- Description
- Gastro-esophageal reflux disease
- Billable
- No – use a more specific code below
- Valid for
- Dates of service October 1, 2026 – September 30, 2027 (FY2027)
- Chapter
- 11. Diseases of the digestive system (K00-K95)
- Block
- K20-K31 Diseases of esophagus, stomach and duodenum
Billable codes under K21
K21 is a header code and cannot be used on claims. Choose the most specific code:
- K21.0 – Gastro-esophageal reflux disease with esophagitisHeader (more codes below)
- K21.9 – Gastro-esophageal reflux disease without esophagitisBillable
Notes for K21
Excludes1 (not coded here):
- newborn esophageal reflux (P78.83)
Notes inherited from parent codes
Instructional notes at a category or block level apply to every code below it.
Block K20-K31
Excludes2 (not included here):
- hiatus hernia (K44.-)
Frequently asked questions
What is ICD-10 code K21?
K21 is the ICD-10-CM code for gastro-esophageal reflux disease, in the block K20-K31 (Diseases of esophagus, stomach and duodenum).
Is K21 a billable code?
No. K21 is a header code with more specific child codes; report one of the billable codes listed above.
Source: CDC/NCHS ICD-10-CM FY2027 code files, tabular list and index. Reference only – code assignment must follow the official ICD-10-CM guidelines and documentation in the medical record.