K21

Non-billable

Gastro-esophageal reflux disease

K21 is the ICD-10-CM code for Gastro-esophageal reflux disease. It is a non-billable category code — use a more specific child code such as K21.0 for billing.

Status
Header (non-billable)
Chapter
K00-K95
Subcodes
2
Edition
FY2026

K00-K95 Diseases of the digestive system

What this means — in plain language

MedlinePlus · NIH

What is 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. Stomach contents can then move back up and irritate the esophagus. Having reflux occasionally is…

Read more about GERD at MedlinePlus ↗

Source: U.S. National Library of Medicine (MedlinePlus). Informational only — not medical advice.

Excludes1 — not coded here

  • newborn esophageal reflux (P78.83)

Medications indicated for this condition

FDA labeling

Drugs whose FDA labeling lists this condition's category among its indications. Informational only — not a treatment recommendation or medical advice.

Conditions mapped to this code

MedlinePlus · NIH

Plain-language health-topic references grounded in MedlinePlus (NIH/NLM).

Frequently asked questions

What is ICD-10 code K21?
K21 is the ICD-10-CM code for "Gastro-esophageal reflux disease". It falls under K00-K95 Diseases of the digestive system.
Is K21 a billable code?
No — K21 is a non-billable header code. Use a more specific child code (such as K21.0) for billing.
What are the subcodes of K21?
K21 has 2 more specific child codes, including K21.0, K21.9.
What is excluded from K21?
Excludes1 (not coded here): newborn esophageal reflux (P78.83).

Source: CMS ICD-10-CM FY2026. For informational purposes only — not medical advice. See our medical disclaimer.

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