A Peritoneal Lavage is a type of diagnostic procedure undertaken in order to identify any internal bleeding that may be occurring within the abdominal cavity. The test is often performed as part of the comprehensive assessment of a patient who has just suffered physical trauma dealt to the abdominal region and who is suspected to have internal injuries. The procedure allows the doctors to determine whether or not further surgical operations may be necessary in the event that internal injuries are discovered.

The procedure is performed while the patient is under anesthetics, in order to ensure that the area involved is numbed for the lavage. A surgeon begins the operation by making an incision upon the abdomen, resulting in a small opening in the abdomen. The incision is just large enough to allow the insertion of a catheter into the cavity, to facilitate the aspiration of any fluids that may have built up within the peritoneum.

Findings obtained after the procedure determine the next course of action to be taken. In general, if 10 mL of blood or any other types of enteric fluid are aspirated from the peritoneal cavity, the result is deemed to be positive, indicating that organ injury and perforation may have occurred. This situation requires further surgical treatment to correct whatever wounds that may have been sustained. The absence of pooling of blood or other foreign constituents within the sterile environment of the peritoneal cavity is a negative result; the procedure may then be concluded through the irrigation of the area with a sterile saline solution.