2026 ICD-10-CM Diagnosis Code K66Other disorders of peritoneum

ICD-10-CM Codes›K00–K95›K65-K68›K66

ICD-10-CM K66
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

K66 is a non-billable ICD-10-CM category code for other disorders of peritoneum, so it cannot be submitted on claims. Use a more specific code from this category instead, such as K66.0, K66.1, K66.8, and K66.9.

Code Identity

ICD-10-CM Code
K66
Billable Status
No — Non-Billable Category
Code Describes
Other disorders of peritoneum
Chapter
K65-K68
Diseases of peritoneum and retroperitoneum

Code Classification

ChapterK00–K95Diseases of the digestive system
SectionK65-K68Diseases of peritoneum and retroperitoneum
CategoryK66Other disorders of peritoneum
This CodeK66Other disorders of peritoneum

Specific Coding for Other disorders of peritoneumOverview

Non-specific codes like K66 require more characters. Use one of these billable codes instead:

  • Use K66.0 for Peritoneal adhesions (postprocedural) (postinfection)

  • Use K66.1 for Hemoperitoneum

  • Use K66.8 for Other specified disorders of peritoneum

  • Use K66.9 for Disorder of peritoneum, unspecified

Tabular List NotesGuidance

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

Type 2 Excludes

  • ascites R18
  • peritoneal effusion chronic R18.8

Patient EducationClinical

Peritoneal Disorders

Your peritoneum is the tissue that lines your abdominal wall and covers most of the organs in your abdomen. A liquid, peritoneal fluid, lubricates the surface of this tissue.

Read the full article at MedlinePlus

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

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 K66Overview

Is K66 (Other disorders of peritoneum) a billable code?

No. This is a category header that groups the codes for other disorders of peritoneum, and headers cannot be submitted on claims. Claims for other disorders of peritoneum need a more specific code from this category, such as K66.0, K66.1, and K66.8.