2026 ICD-10-CM Diagnosis Code K57.00Diverticulitis of small intestine with perforation and abscess without bleeding

ICD-10-CM Codes›K00–K95›K55-K64›K57

ICD-10-CM K57.00
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

K57.00 is a billable ICD-10-CM diagnosis code for diverticulitis of small intestine with perforation and abscess without bleeding. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 391 through 392. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 6 closely related codes. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Diverticulosis and diverticulitis, Gastrointestinal and biliary perforation, and Peritonitis and intra-abdominal abscess.

Code Identity

ICD-10-CM Code
K57.00
Billable Status
Yes — Valid for Submission
Code Describes
Diverticulitis of small intestine with perforation and abscess without bleeding
Short Description
Dvtrcli of sm int w perforation and abscess w/o bleeding
Parent Code
K57.0
Diverticulitis of small intestine with perforation and abscess

Code Classification

ChapterK00–K95Diseases of the digestive system
SectionK55-K64Other diseases of intestines
CategoryK57Diverticular disease of intestine
This CodeK57.00Diverticulitis of small intestine with perforation and abscess without bleeding

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Abscess of duodenum co-occurrent and due to diverticulitis
  • Abscess of ileum co-occurrent and due to diverticulitis
  • Abscess of jejunum co-occurrent and due to diverticulitis
  • Diverticulitis of duodenum
  • Diverticulitis of ileum
  • Diverticulitis of jejunum
  • Diverticulitis of jejunum with perforation
  • Diverticulitis of small intestine with perforation and abscess
  • Hemorrhage of small intestine due to diverticulitis
  • Jejunitis
  • Perforated diverticulum of duodenum
  • Perforated diverticulum of ileum
  • Perforated diverticulum of intestine
  • Perforated diverticulum of jejunum
  • Perforated diverticulum of small intestine
  • Perforation of duodenum due to diverticulitis
  • Perforation of ileum
  • Perforation of ileum due to diverticulitis
  • Perforation of small intestine co-occurrent with hemorrhage due to diverticulitis
  • Perforation of small intestine due to diverticulitis

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 DIG013
Diverticulosis and diverticulitis
Default principal diagnosis: inpatient Yes · outpatient Yes
CCSR DIG006
Gastrointestinal and biliary perforation
Default principal diagnosis: inpatient No · outpatient No
CCSR DIG016
Peritonitis and intra-abdominal abscess
Default principal diagnosis: inpatient No · outpatient No

Patient EducationClinical

Abscess

An abscess is a pocket of pus. You can get an abscess almost anywhere in your body. When an area of your body becomes infected, your body's immune system tries to fight the infection. White blood cells go to the infected area, collect within the damaged tissue, and cause inflammation. During this process, pus forms.

Read the full article at MedlinePlus

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

Convert K57.00 to ICD-9-CMHistory

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

ICD-9-CM
562.01 Dvrtcli sml int w/o hmrg
ApproximateCombination The match is approximate, and more than one code can be needed to describe the source diagnosis. Confirm with contextual judgment.
ICD-9-CM
569.5 Intestinal abscess
ApproximateCombination The match is approximate, and more than one code can be needed to describe the source diagnosis. Confirm with contextual judgment.

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 K57.00Overview

Is K57.00 a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report diverticulitis of small intestine with perforation and abscess without bleeding on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does K57.00 group to?

When diverticulitis of small intestine with perforation and abscess without bleeding is the principal diagnosis on an inpatient stay, it groups to MS-DRG 391, 392, with relative weights from 0.7796 to 1.2683 depending on complications. Higher weights mean higher Medicare reimbursement.

Is K57.00 a CC or MCC?

CMS lists K57.00 as a CC (complication or comorbidity) for FY 2026. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 6 closely related codes in its exclusion list.

What is the ICD-9 equivalent of K57.00?

Under the General Equivalence Mappings, diverticulitis of small intestine with perforation and abscess without bleeding converts to ICD-9-CM 562.01 (dvrtcli sml int w/o hmrg) and 569.5 (intestinal abscess). The mapping is approximate, so confirm the match fits the documentation.