2026 ICD-10-CM Diagnosis Code K66.1Hemoperitoneum
ICD-10-CM Codes›K00–K95›K65-K68›K66
- Billable — Valid for Submission
- Not Chronic
K66.1 is a billable ICD-10-CM diagnosis code for hemoperitoneum. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 393 through 395. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified and unspecified gastrointestinal disorders.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Hematoma of extraperitoneal space
- Hemoperitoneum as complication of peritoneal dialysis
- Hemorrhage into peritoneal cavity
- Intra-abdominal hematoma
- Intraperitoneal hematoma
- Nontraumatic hemoperitoneum
- Omental hemorrhage
- Perinephric hematoma
- Retroperitoneal hematoma
- Retroperitoneal hemorrhage
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Inclusion Terms
- Peritoneal hematoma
- Peritoneal hemorrhage
Type 1 Excludes
- traumatic hemoperitoneum S36.8
Type 2 Excludes
These terms are the conditions for which that code is to be used. The terms may be synonyms of the code title, or, in the case of "other specified" codes, the terms are a list of the various conditions assigned to that code. The inclusion terms are not necessarily exhaustive. Additional terms found only in the Alphabetic Index may also be assigned to a code.
A type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.
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.
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
- Hematoma (traumatic) (skin surface intact) - See Also: Contusion;
- peritoneal - K66.1
- Hemoperitoneum - K66.1
- Hemorrhage, hemorrhagic (concealed) - R58
- male - K66.1
- intraperitoneal - K66.1
- mesentery - K66.1
- omentum - K66.1
- peritoneum, peritoneal - K66.1
External Cause of Injuries IndexGuidance
References for this code in the External Cause of Injuries Index.
- Hematoma(traumatic) (skin surface intact)
- peritoneal
- Hemoperitoneum
- Hemorrhage, hemorrhagic(concealed)
- intrapelvic
- male
- Hemorrhage, hemorrhagic(concealed)
- intraperitoneal
- Hemorrhage, hemorrhagic(concealed)
- mesentery
- Hemorrhage, hemorrhagic(concealed)
- omentum
- Hemorrhage, hemorrhagic(concealed)
- peritoneum, peritoneal
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Hemoperitoneum
accumulations of blood in the peritoneal cavity due to internal hemorrhage.Perinephric Hematoma
a collection of blood around the kidney.
Patient EducationClinical
Gastrointestinal Bleeding
Your digestive or gastrointestinal (GI) tract includes the esophagus, stomach, small intestine, large intestine or colon, rectum, and anus. Bleeding can come from any of these areas. The amount of bleeding can be so small that only a lab test can find it.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert K66.1 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About K66.1Overview
Is K66.1 (Other disorders of peritoneum) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report hemoperitoneum on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does K66.1 group to?
When hemoperitoneum is the principal diagnosis on an inpatient stay, it groups to MS-DRG 393, 394, 395, with relative weights from 0.6490 to 1.5993 depending on complications. Higher weights mean higher Medicare reimbursement.
What is the ICD-9 equivalent of K66.1?
Under the General Equivalence Mappings, hemoperitoneum converts to ICD-9-CM 568.81 (hemoperitoneum). 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.
