2026 ICD-10-CM Diagnosis Code K81.1Chronic cholecystitis

ICD-10-CM Codes›K00–K95›K80-K87›K81

ICD-10-CM K81.1
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

K81.1 is a billable ICD-10-CM diagnosis code for chronic cholecystitis. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 444 through 446. Coders also document this condition as cholecystitis glandularis proliferans. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Biliary tract disease.

Code Identity

ICD-10-CM Code
K81.1
Billable Status
Yes — Valid for Submission
Code Describes
Chronic cholecystitis
Short Description
Chronic cholecystitis
Same as the full description in the CMS dataset.
Parent Code
K81
Cholecystitis

Code Classification

ChapterK00–K95Diseases of the digestive system
SectionK80-K87Disorders of gallbladder, biliary tract and pancreas
CategoryK81Cholecystitis
This CodeK81.1Chronic cholecystitis

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Cholecystitis glandularis proliferans
  • Cholecystitis without calculus
  • Chronic cholecystitis
  • Chronic cholecystitis without calculus

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.

    • Cholecystitis
      • chronic

Clinical ClassificationClinical

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

CCSR DIG017
Biliary tract disease
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Chronic Cholecystitis

    cholecystitis that is persistent and long-standing.

Patient EducationClinical

Gallbladder Diseases

Your gallbladder is a pear-shaped organ under your liver. It stores bile, a fluid made by your liver to digest fat. As your stomach and intestines digest food, your gallbladder releases bile through a tube called the common bile duct. The duct connects your gallbladder and liver to your small intestine.

Read the full article at MedlinePlus

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

Convert K81.1 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
575.11 Chronic cholecystitis
Exact Match The mapping is direct, with no qualifiers.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About K81.1Overview

Is K81.1 (Cholecystitis) a billable code?

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

What MS-DRG does K81.1 group to?

When chronic cholecystitis is the principal diagnosis on an inpatient stay, it groups to MS-DRG 444, 445, 446, with relative weights from 0.8273 to 1.6709 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of K81.1?

Under the General Equivalence Mappings, chronic cholecystitis converts to ICD-9-CM 575.11 (chronic cholecystitis). The mapping is a direct match.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.