2026 ICD-10-CM Diagnosis Code K63.822Small intestinal fungal overgrowth

ICD-10-CM Codes›K00–K95›K55-K64›K63

ICD-10-CM K63.822
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

K63.822 is a billable ICD-10-CM diagnosis code for small intestinal fungal overgrowth. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 393 through 395. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified and unspecified gastrointestinal disorders.

Code Identity

ICD-10-CM Code
K63.822
Billable Status
Yes — Valid for Submission
Code Describes
Small intestinal fungal overgrowth
Short Description
Small intestinal fungal overgrowth
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 CodeK63.822Small intestinal fungal overgrowth

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Overgrowth
      • fungal
        • small intestinal

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

Code History & ChangesHistory

Replacement K63.822 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 2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About K63.822Overview

Is K63.822 (Small intestinal bacterial overgrowth) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report small intestinal fungal overgrowth on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does K63.822 group to?

When small intestinal fungal overgrowth is the principal diagnosis on an inpatient stay, it groups to MS-DRG 393, 394, 395, with relative weights from 0.6490 to 1.5993 depending on complications. Higher weights mean higher Medicare reimbursement.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.