Peritoneal fluid culture is a laboratory test performed on a sample of peritoneal fluid to isolate and identify the presence of microorganisms that cause infection (peritonitis).

Peritoneal fluid is the fluid from the peritoneal cavity, a space between two membranes lining the abdominal cavity.

The test is performed by abdominal tap, a needle aspiration of the peritoneal cavity. A sample of fluid is sent to the laboratory for gram stain and culture preparation. The sample is examined regularly for the growth of microorganisms.

Empty your bladder before your abdominal tap procedure.

A small area in your abdomen will be cleaned with an antiseptic. You will also receive local anesthesia. You will then feel pressure as the needle is inserted. If a large amount of fluid is withdrawn, you may feel dizzy or light-headed.

The test is done to find out if there is an infection in the peritoneal space.

Peritoneal fluid is a sterile fluid, so normally no organisms are present.

The growth of any microorganism, such as bacteria or fungi, from peritoneal fluid is abnormal and represents peritonitis.

There is a small risk of the needle puncturing the bowel, bladder, or a blood vessel in the abdomen, possibly resulting in bowel perforation, bleeding, and infection.

The diagnosis of peritonitis is based on more than just the peritoneal fluid culture (which may remain negative even in the presence of peritonitis).