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Brain & Nervous System Health Center

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Paracentesis is a procedure to take out fluid that has collected in the belly (peritoneal fluid). This fluid buildup is called ascites camera.gif. The fluid taken from your belly will be sent to a lab to be studied and looked at under a microscope. Results will be ready in a few hours.


No infection, cancer, or abnormal values are found.


Several tests may be done on the fluid.

  • Cell counts. A high number of white blood cells (WBCs) in the fluid may mean inflammation, infection (peritonitis), or cancer is present. A high WBC count and a high count of WBCs called polymorphonuclear leukocytes (PMNs) may mean there is an infection inside the belly called spontaneous bacterial peritonitis (SBP).
  • Serum-ascites albumin gradient (SAAG). The SAAG compares the level of protein in the fluid to the level of protein in the blood. High protein levels in the fluid may mean cancer, tuberculosis, nephrotic syndrome, or pancreatitis. Low protein levels in the fluid may mean cirrhosis or clots in veins of the liver are present.
  • Culture. A culture can be done on the fluid to see whether bacteria or other infectious organisms are present.
  • Lactate dehydrogenase (LDH). High levels of the enzyme LDH may mean infection or cancer is present.
  • Cytology. Abnormal cells in the fluid may mean cancer is present.
  • Amylase. High levels of amylase may mean pancreatitis or that there is a hole in the intestine.
  • Glucose. Low levels of glucose may mean infection.

What Affects the Test

Reasons you may not be able to have the test or why the results may not be helpful include:

  • Using blood thinners (anticoagulants) or aspirin, which can increase the chance of bleeding.
  • Having blood, bile, urine, or feces in the fluid sample.
  • Not being able to stay still during the test.
  • Being obese.
  • Having scars inside the belly (adhesions) from any belly surgery in the past.

What To Think About

Sometimes doctors use fluids put into the belly to check for injuries. This is called peritoneal lavage. During this procedure, a doctor uses a paracentesis needle to put a salt (saline) fluid into the belly. The fluid is then taken out through the same needle. If the fluid that comes out is bloody, the bleeding is probably being caused by an injury inside the belly.

WebMD Medical Reference from Healthwise

Last Updated: November 14, 2014
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

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