ICD-10-CM category K21: Gastro-esophageal reflux disease
Category K21 is a heading in chapter 11 (Diseases of the digestive system (K00-K95)), section Diseases of esophagus, stomach and duodenum (K20-K31). It is not billable; report one of the 3 complete codes below.
Notes that apply to every K21 code
- Excludes1 (never coded together)
- newborn esophageal reflux (P78.83)
Billable codes in K21
Sources
Every figure on this page is taken from the CMS publications below, as released by the Centers for Medicare & Medicaid Services. Projection built 2026-10-10. Verify against the primary file before billing or contracting decisions. The reference methodology explains how each figure is computed from these files.
- ICD-10-CM FY2027 tabular order file (category titles)Version FY2027 · effective 2026-10-01 · file icd10cm_order_2027.txtSHA-256 38981fb2c1226e2b…
- ICD-10-CM FY2027 tabular list (chapter titles and ranges)Version FY2027 · effective 2026-10-01 · file 2027-code-tables-tabular-index.zipSHA-256 37baa476323714be…
- ICD-10-CM FY2027 code descriptions addenda (codes added, deleted and revised)Version FY2027 · effective 2026-10-01 · file icd10cm_codes_addenda_2027.txtSHA-256 cfba025073235af4…
- ICD-10 MS-DRG Definitions Manual v44 (text)Version v44 · effective 2026-10-01 · file fy2027-fr-icd10-ms-drg-definitions-manual-files-v44.zipSHA-256 ae4f6c11727fe91f…
- IPPS FY2027 Tables 6A-6K: new, invalid and revised ICD-10-CM/PCS codes, CC/MCC list changes and CC exclusionsVersion FY2027 (final rule; not reissued by CN3) · effective 2026-10-01 · file fy2027-ipps-fr-tables-6a-6k.zipSHA-256 ca0af87b0869a405…
- ICD-10-CM FY2027 POA-exempt codes (full list, additions, deletions and revisions)Version FY2027 · effective 2026-10-01 · file 2027-poa-exempt-codes.zipSHA-256 03f55091045024d0…
- ICD-10-CM to CMS-HCC V28 mappings, payment year 2027 initialVersion PY2027 initial ICD-10-CM mappings (dates of service 2026) · effective 2027-01-01 · file 2027 Initial ICD-10-CM Mappings.csvSHA-256 9c260b06d0dd2806…
- Medicare Coverage Database, current Billing and Coding Articles exportVersion MCD release 2026-10-08 · effective 2026-10-04 · file article.csvSHA-256 5e95c4a8ac3664be…
Codes from the FY2027 ICD-10-CM files (all chapters). Report the code that matches the documentation and the Official Guidelines; this list is not coding advice.