2022 ICD-10-CM Code K66.9

Disorder of peritoneum, unspecified

Version 2021

Valid for Submission

ICD-10:K66.9
Short Description:Disorder of peritoneum, unspecified
Long Description:Disorder of peritoneum, unspecified

Code Classification

  • Diseases of the digestive system (K00–K93)
    • Diseases of peritoneum and retroperitoneum (K65-K68)
      • Other disorders of peritoneum (K66)

K66.9 is a billable diagnosis code used to specify a medical diagnosis of disorder of peritoneum, unspecified. The code K66.9 is valid during the fiscal year 2022 from October 01, 2021 through September 30, 2022 for the submission of HIPAA-covered transactions.

The ICD-10-CM code K66.9 might also be used to specify conditions or terms like disorder of pelvic peritoneum or disorder of peritoneum.

Unspecified diagnosis codes like K66.9 are acceptable when clinical information is unknown or not available about a particular condition. Although a more specific code is preferable, unspecified codes should be used when such codes most accurately reflect what is known about a patient's condition. Specific diagnosis codes should not be used if not supported by the patient's medical record.

Index to Diseases and Injuries

The Index to Diseases and Injuries is an alphabetical listing of medical terms, with each term mapped to one or more ICD-10 code(s). The following references for the code K66.9 are found in the index:

Approximate Synonyms

The following clinical terms are approximate synonyms or lay terms that might be used to identify the correct diagnosis code:

Convert K66.9 to ICD-9 Code

Information for Patients


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.

Disorders of the peritoneum are not common. They include

Your doctor may use imaging tests or lab tests to analyze the peritoneal fluid to diagnose the problem. Treatment of peritoneal disorders depends on the cause.


[Learn More in MedlinePlus]

Code History

  • FY 2021 - No Change, effective from 10/1/2020 through 9/30/2021
  • FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020
  • FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
  • FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018
  • FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
  • FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016 (First year ICD-10-CM implemented into the HIPAA code set)