Other disorders of peritoneum (K66) ICD-10-CM
The K66 code range covers other disorders of peritoneum with 5 ICD-10-CM diagnosis codes. 4 of them are billable and valid for claim submission in fiscal year 2026, and the category headers group them but cannot themselves be billed.
Type 2 Excludes
A type 2 excludes note represents "Not included here". An excludes2 note indicates that the condition excluded is not part of the condition represented by the code, but a patient may have both conditions at the same time. When an Excludes2 note appears under a code, it is acceptable to use both the code and the excluded code together, when appropriate.
Codes in the K66 Range 5 codes · 4 billable
Clinical Terms in This Code Range
Definitions from the National Library of Medicine for conditions coded in the K66 range.
Hemoperitoneum
Accumulations of blood in the PERITONEAL CAVITY due to internal HEMORRHAGE.
Mesenteric Cyst
A rare intra-abdominal tumor in the MESENTERY. Mesenteric cysts are usually benign and can be very large fluid-filled (2000 mL) lesions.
Peritoneal Fibrosis
Disorder characterized by a wide range of structural changes in PERITONEUM, resulting from fibrogenic or inflammatory processes. Peritoneal fibrosis is a common complication in patients receiving PERITONEAL DIALYSIS and contributes to its gradual decrease in efficiency.
Pneumoperitoneum
A condition with trapped gas or air in the PERITONEAL CAVITY, usually secondary to perforation of the internal organs such as the LUNG and the GASTROINTESTINAL TRACT, or to recent surgery. Pneumoperitoneum may be purposely introduced to aid radiological examination.
Pneumoperitoneum, Artificial
Deliberate introduction of air into the peritoneal cavity.
About the K66 Code Range
The ICD-10 codes in the K66 category cover various disorders affecting the peritoneum, the thin membrane lining the abdominal cavity. These codes specify conditions like peritoneal adhesions, hemoperitoneum, other named peritoneal disorders, and unspecified peritoneal conditions.
The ICD-10 code for peritoneal adhesions (K66.0) captures conditions where scar tissue forms after surgery or infection, binding organs such as the intestines, stomach, or pelvic peritoneum. Common synonyms include "intestinal entrapment" and "adhesion of mesentery," helping coders identify this code when these terms appear in documentation. K66.1 refers to hemoperitoneum, the presence of blood within the peritoneal cavity, also known by terms like "omental hemorrhage" or "retroperitoneal hematoma." The code K66.8 groups other specified peritoneal disorders including "frozen pelvis syndrome," "peritoneal pseudocyst," and "peritoneal fibrosis." Lastly, K66.9 is used when a peritoneal disorder is documented but not specified further, often noted as "disorder of pelvic peritoneum."
These detailed ICD-10 codes enable precise classification of peritoneal conditions, facilitating accurate medical record keeping and billing for care related to abdominal and pelvic membrane disorders.
Questions About This Page
How many billable codes are in the K66 range?
Of the 5 codes in this range, 4 are billable and valid for claim submission from October 1, 2025 through September 30, 2026. Category header codes group them but cannot be reported on claims.
What does the K66 range classify?
The range classifies other disorders of peritoneum. Each code links to its own reference page with billing status, MS-DRG grouping, coding notes, and clinical information.
Related References
Source: CMS FY 2026 ICD-10-CM Tabular List and order file, effective October 1, 2025 through September 30, 2026.
