2027 ICD-10-CM Diagnosis Code K63.8211Small intestinal bacterial overgrowth, hydrogen-subtype

ICD-10-CM Codes›K00–K95›K55-K64›K63

ICD-10-CM K63.8211
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

K63.8211 is a billable ICD-10-CM diagnosis code for small intestinal bacterial overgrowth, hydrogen-subtype. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 393 through 395. Coders also document this condition as bacterial overgrowth syndrome. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified and unspecified gastrointestinal disorders.

Code Identity

ICD-10-CM Code
K63.8211
Billable Status
Yes — Valid for Submission
Code Describes
Small intestinal bacterial overgrowth, hydrogen-subtype
Short Description
Small intestinal bacterial overgrowth, hydrogen-subtype
Same as the full description in the CMS dataset.
Parent Code
K63.821
Small intestinal bacterial overgrowth

Code Classification

ChapterK00–K95Diseases of the digestive system
SectionK55-K64Other diseases of intestines
CategoryK63Other diseases of intestine
This CodeK63.8211Small intestinal bacterial overgrowth, hydrogen-subtype

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Bacterial overgrowth syndrome
  • Small bowel bacterial overgrowth syndrome
  • Small bowel bacterial overgrowth syndrome caused by hydrogen producing bacteria

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to K63.8211: its own notes plus those printed at Chapter 11. A note printed at a category, block or chapter applies to every code under it.

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 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.

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR DIG025
Other specified and unspecified gastrointestinal disorders
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Small Intestine Disorders

Your small intestine is the longest part of your digestive system - about twenty feet long! It connects your stomach to your large intestine (or colon) and folds many times to fit inside your abdomen. Your small intestine does most of the digesting of the foods you eat. It has three areas called the duodenum, the ileum, and the jejunum.

Read the full article at MedlinePlus

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

Code History & ChangesHistory

Replacement K63.8211 replaces the following previously assigned code(s):

  • K63.89 - Other specified diseases of intestine
FY 2024AddedAdded to the ICD-10-CM code setEffective October 1, 2023.
FY 2025–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About K63.8211Overview

What is the ICD-10 code for small intestinal bacterial overgrowth, hydrogen-subtype?

The ICD-10-CM code for small intestinal bacterial overgrowth, hydrogen-subtype is K63.8211 (sometimes written as K638211). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is K63.8211 (Small intestinal bacterial overgrowth) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report small intestinal bacterial overgrowth, hydrogen-subtype on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does K63.8211 group to?

When small intestinal bacterial overgrowth, hydrogen-subtype is the principal diagnosis on an inpatient stay, it groups to MS-DRG 394, 395, 393, with relative weights from 0.6379 to 1.5877 depending on complications. Higher weights mean higher Medicare reimbursement.