Is K21.01 a billable ICD-10-CM code?

Yes. K21.01 is a billable, specific ICD-10-CM code and is valid for submission on a claim.

Where does K21.01 sit in the tabular list?

Diseases of the digestive system (K00-K95), in the block Diseases of esophagus, stomach and duodenum (K20-K31).

What cannot be coded together with K21.01?

K21.01 carries Excludes1 notes, which means the conditions they list can never be coded together with it on the same encounter. Some are written on the categories above K21.01 (K21) and apply to it just the same.

K21.01

K21.01 — Gastro-esophageal reflux disease with esophagitis, with bleeding

Billable / specific codeICD-10-CM

K21.01 is a billable, specific ICD-10-CM code for gastro-esophageal reflux disease with esophagitis, with bleeding. It is valid for submission on a claim.

Excludes1 inherited from the categories above K21.01

These are not written on K21.01, but they bind it: a note on a category applies to every code beneath it. Billing K21.01 with anything listed here is a denial.

Written on K21 — Gastro-esophageal reflux disease

newborn esophageal reflux (P78.83)

Risk adjustment

K21.01 does not map to an HCC and does not risk-adjust under CMS-HCC V28. That is normal — most ICD-10 codes do not. It still needs to be coded correctly; it just will not move a RAF score.

Medicare coverage

K21.01 is named in 18 Medicare coverage policies — 14 listing it as supporting medical necessity, and 4 listing it as NOT covered. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.

A59015Billing and Coding: MolDX: Molecular Testing for Detection of Upper Gastrointestinal Metaplasia, Dysplasia, and Neoplasianot covered
A59032Billing and Coding: MolDX: Molecular Testing for Detection of Upper Gastrointestinal Metaplasia, Dysplasia, and Neoplasianot covered
A59051Billing and Coding: MolDX: Molecular Testing for Detection of Upper Gastrointestinal Metaplasia, Dysplasia, and Neoplasianot covered
A59121Billing and Coding: MolDX: Molecular Testing for Detection of Upper Gastrointestinal Metaplasia, Dysplasia, and Neoplasianot covered

How K21.01 is indexed

Coders do not find codes by browsing the tabular list — they look them up in the alphabetic index, under the word the physician wrote. These are the index entries that lead here, so you can see which chart wordings map to K21.01.

Esophagitis›due to gastrointestinal reflux disease›with bleeding
Esophagitis›reflux›with bleeding
Disease, diseased›gastroesophageal reflux›with esophagitis›with bleeding
Reflux›esophageal›with esophagitis›with bleeding
Reflux›gastroesophageal›with esophagitis›with bleeding
Allergy, allergic›milk protein›gastroesophageal reflux›with esophagitis›with bleeding
Ulcer, ulcerated, ulcerating, ulceration, ulcerative›esophagus›due to›gastrointestinal reflux disease›with bleeding

The condition this code belongs to

Every code for the condition on one page, which one applies when, and the mistake coders make with it.

GERD (gastro-oesophageal reflux disease) ICD-10 codes

Code history

K21.01 has not changed since FY2024 — no addition, revision or deletion across the three most recent ICD-10-CM releases.

Related codes at this level

Codes that share K21.0. If K21.01 is not quite right, the correct code is usually one of these.

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

Questions about K21.01

Is K21.01 a billable ICD-10-CM code?: Yes. K21.01 is a billable, specific ICD-10-CM code and is valid for submission on a claim.
Where does K21.01 sit in the tabular list?: Diseases of the digestive system (K00-K95), in the block Diseases of esophagus, stomach and duodenum (K20-K31).
What cannot be coded together with K21.01?: K21.01 carries Excludes1 notes, which means the conditions they list can never be coded together with it on the same encounter. Some are written on the categories above K21.01 (K21) and apply to it just the same.