2026 ICD-10-CM Diagnosis Code K81.0Acute cholecystitis

ICD-10-CM Codes›K00–K95›K80-K87›K81

ICD-10-CM K81.0
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

K81.0 is a billable ICD-10-CM diagnosis code for acute 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. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Biliary tract disease.

Code Identity

ICD-10-CM Code
K81.0
Billable Status
Yes — Valid for Submission
Code Describes
Acute cholecystitis
Short Description
Acute 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 CodeK81.0Acute cholecystitis

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Abscess of gallbladder
  • Acute angiocholecystitis
  • Acute cholecystitis
  • Acute cholecystitis without calculus
  • Acute emphysematous cholecystitis
  • Acute gangrenous cholecystitis
  • Acute hemorrhagic cholecystitis
  • Acute suppurative cholecystitis
  • Angiocholecystitis
  • Cholecystitis without calculus
  • Empyema of gallbladder
  • Gangrene of gallbladder
  • Infective cholangitis
  • Pericholecystic abscess
  • Pneumocholecystitis

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • Abscess of gallbladder
  • Angiocholecystitis
  • Emphysematous (acute) cholecystitis
  • Empyema of gallbladder
  • Gangrene of gallbladder
  • Gangrenous cholecystitis
  • Suppurative cholecystitis

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.

    • Abscess(connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic)
      • gallbladder
    • Cholecystitis
      • acute (emphysematous) (gangrenous) (suppurative)
    • Empyema(acute) (chest) (double) (pleura) (supradiaphragmatic) (thorax)
      • gallbladder
    • Gallbladder
      • acute
    • Septic
      • gallbladder (acute)
    • Suppuration, suppurative
      • gallbladder (acute)

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

  • Acute Cholecystitis

    acute inflammation of the gallbladder.

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 K81.0 to ICD-9-CMHistory

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

ICD-9-CM
575.0 Acute 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 K81.0Overview

Is K81.0 (Cholecystitis) a billable code?

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

What MS-DRG does K81.0 group to?

When acute 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 K81.0?

Under the General Equivalence Mappings, acute cholecystitis converts to ICD-9-CM 575.0 (acute cholecystitis). The mapping is a direct match.

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.