How the Test is Performed

The sample of fluid is removed from the peritoneal space using a needle and syringe.

Your health care provider will clean and numb a small area of your belly area (abdomen). Next, your health care provider will insert a needle through the skin of your abdomen into the peritoneal space, and pull out a sample of fluid. The fluid collects into a tube (syringe) attached to the end of the needle.

See: Abdominal tap

The fluid is sent to a laboratory where it is examined. Tests will be done on the fluid to measure:

• Albumin
• Protein
• Red and white blood cell counts

Tests will also check for bacteria and other types of infection.

Sometimes, the following tests are also done:

• Alkaline phosphatase
• Amylase
• Cytology (appearance of cells)
• Glucose
• LDH

How to Prepare for the Test

Let your health care provider know if you:

• Are taking any medications (including herbal remedies)
• Have any allergies to medications or numbing medicine
• Have any bleeding problems
• Might be pregnant

How the Test Will Feel

You may feel a stinging sensation from the numbing medicine, or pressure as the needle is inserted.

If a large amount of fluid is taken out, you may feel dizzy or light-headed. Tell the health care provider if you feel dizzy.

Why the Test is Performed

The test is done to:

• Detect peritonitis
• Find the cause of fluid in the abdomen
• Remove large amounts of fluid from the peritoneal space in people who have liver disease
• See whether an injury to the abdomen has caused internal bleeding

What Abnormal Results Mean

• Bile-stained fluid may mean you have a gallbladder or liver problem.
• Bloody fluid may be a sign of tumor or injury.
• High white blood cell counts may be a sign of peritonitis.
• Milk-colored peritoneal fluid may be a sign of carcinoma, cirrhosis of the liver, lymphoma, tuberculosis, or infection.

Other abnormal test results may be due to a problem in the intestines or organs of the abdomen. Large differences between the amount of albumin in the peritoneal fluid and in your blood may point to heart, liver, or kidney failure. Small differences may be a sign of cancer or infection.

Risks

• Damage to the bowel, bladder, or a blood vessel in the abdomen from a needle puncture
• Infection
• Low blood pressure
• Shock

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.

Runyon BA. Ascites and spontaneous bacterial peritonitis. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger and Fordtran's Gastrointestinal and Liver Disease. 9th ed. Philadelphia, Pa: Saunders Elsevier; 2010:chap 91.

Update Date: 2/4/2012

Reviewed by: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and George F Longstreth, MD, Department of Gastroenterology, Kaiser Permanente Medical Care Program San Diego, California. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.