Peritoneal fluid culture

Definition

Peritoneal fluid culture is a laboratory test performed on a sample of peritoneal fluid to detect bacteria or fungi that cause infection (peritonitis).

Peritoneal fluid is the fluid from the peritoneal cavity, a space between the wall of the abdomen and the organs inside.

Alternative Names

Culture - peritoneal fluid

How the test is performed

The test is performed by abdominal tap (paracentesis), a needle aspiration of the peritoneal cavity. A sample of fluid is sent to the laboratory for Gram stain and culture. The sample is examined regularly for bacterial growth.

How to prepare for the test

Empty your bladder before your abdominal tap procedure.

How the test will feel

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 If a large amount of fluid is withdrawn, you may feel dizzy or light-headed.

Why the test is performed

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

Normal Values

Peritoneal fluid is a sterile fluid, so normally no bacteria or fungi are present.

What abnormal results mean

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

What the risks are

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

Special considerations

The diagnosis of peritonitis is based on more than just the peritoneal fluid culture (which may be negative even if you have peritonitis).

References

Garcia-Tsao G. Cirrhosis and its sequelae. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier;2007:chap 157.