2027 ICD-10-CM Diagnosis Code K21Gastro-esophageal reflux disease

ICD-10-CM Codes›K00–K95›K20-K31›K21

ICD-10-CM K21
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

K21 is a non-billable ICD-10-CM category code for gastro-esophageal reflux disease, so it cannot be submitted on claims. Use a more specific code from this category instead, such as K21.00, K21.01, and K21.9.

Code Identity

ICD-10-CM Code
K21
Billable Status
No — Non-Billable Category
Code Describes
Gastro-esophageal reflux disease
Short Description
Gastro-esophageal reflux disease
Same as the full description in the CMS dataset.
Chapter
K20-K31
Diseases of esophagus, stomach and duodenum

Code Classification

ChapterK00–K95Diseases of the digestive system
SectionK20-K31Diseases of esophagus, stomach and duodenum
CategoryK21Gastro-esophageal reflux disease
This CodeK21Gastro-esophageal reflux disease

Specific Coding for Gastro-esophageal reflux diseaseOverview

Non-specific codes like K21 require more characters. Use one of these billable codes instead:

  • K21.0 for Gastro-esophageal reflux disease with esophagitis

  • Use K21.00 for Gastro-esophageal reflux disease with esophagitis, without bleeding

  • Use K21.01 for Gastro-esophageal reflux disease with esophagitis, with bleeding

  • Use K21.9 for Gastro-esophageal reflux disease without esophagitis

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to K21: its own notes plus those printed at block K20-K31 and Chapter 11. A note printed at a category, block or chapter applies to every code under it.

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

  • newborn esophageal reflux (P78.83)

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From Block K20-K31 Diseases of esophagus, stomach and duodenum applies to 106 codes
From Chapter 11 (K00-K95) Diseases of the digestive system applies to 863 codes
  • 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)

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name K21, its category, or a range that includes it.

Code Also 2

These codes say K21 may also be needed to fully describe the condition. The note gives no sequencing direction.

  • R63.31 Pediatric feeding disorder, acute
    gastro-esophageal reflux disease (K21.-)
  • R63.32 Pediatric feeding disorder, chronic
    gastro-esophageal reflux disease (K21.-)

Clinical InformationClinical

  • Gastroesophageal Reflux

    retrograde flow of gastric juice (gastric acid) and/or duodenal contents (bile acids; pancreatic juice) into the distal esophagus, commonly due to incompetence of the lower esophageal sphincter.

Patient EducationClinical

GERD

Sometimes, after eating a large meal or lying down too soon after eating, you might feel acid coming up into your throat. This is called gastroesophageal reflux (GER). It happens when the muscle at the end of your esophagus (the tube that carries food from your mouth to your stomach) doesn't close properly.

The full article covers:

  • What is GERD?
  • What causes GERD?
  • What are common symptoms of GERD?
  • How is GERD diagnosed?
  • How is GERD treated?
  • Can GERD be prevented?

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About K21Overview

What is the ICD-10 code for gastro-esophageal reflux disease?

K21 is the ICD-10-CM category for gastro-esophageal reflux disease, but it is a non-billable header: claims need a more specific code from this category, listed on this page.

Is K21 (Gastro-esophageal reflux disease) a billable code?

No. This is a category header that groups the codes for gastro-esophageal reflux disease, and headers cannot be submitted on claims. Claims for gastro-esophageal reflux disease need a more specific code from this category, such as K21.00, K21.01, and K21.9.

Can K21 be reported with P78.83?

Not as a rule. The Excludes1 note on K21 lists "newborn esophageal reflux (P78.83)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).