Abdominal tap

• Alternative Names

  Peritoneal tap; Paracentesis

• How the test is performed

  This test may be done in an office setting, treatment room, or hospital.

  The puncture site will be cleaned and shaved, if necessary. You then receive a local numbing medicine. The tap needle is inserted 1 - 2 inches into the abdomen. Sometimes a small cut is made to help insert the needle. The fluid is pulled out into a syringe.

  The needle is removed. A dressing is placed on the puncture site. If a cut was made, one or two stitches may be used to close it.

  There are two kinds of abdominal taps:

  • Diagnostic tap -- a small amount of fluid is taken and sent to the laboratory for testing
  • Large volume tap -- several liters may be removed to relieve abdominal pain and fluid buildup
• How to prepare for the test

  Let your health care provider know if you:

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

  Infants and children:

  The preparation you can provide for this test depends on your child's age, previous experience, and level of trust. For general information regarding how you can prepare your child, see the following topics:

  • Infant test/procedure preparation (birth - 1 year)
  • Toddler test/procedure preparation (1 - 3 years)
  • Preschooler test/procedure preparation (3 - 6 years)
  • School age test/procedure preparation (6 - 12 years)
  • Adolescent test/procedure preparation (12 - 18 years)
• 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

  Normally, the abdomen contains only a small amount of fluid. In certain conditions, large amounts of fluid can build up in the abdomen.

  An abdominal tap may be done to diagnose the cause of fluid buildup. It may also be done to diagnose infected abdominal fluid, or to remove a large amount of fluid to reduce abdominal pain.

• Normal Values

  Normally, there should be little or no fluid in the abdomen.

• What abnormal results mean

  An examination of abdominal fluid may show:

  • Appendicitis
  • Cirrhosis of the liver
  • Damaged bowel
  • Heart disease
  • Infection
  • Kidney disease
  • Pancreatic disease
  • Tumor (cancerous or noncancerous)
• What the risks are

  There is a slight chance of the needle puncturing the bowel, bladder, or a blood vessel in the abdomen. If a large quantity of fluid is removed, there is a slight risk of lowered blood pressure and kidney failure. There is also a slight chance of infection.

Review Date: 8/22/2008

Reviewed By: Christian Stone, MD, Division of Gastroenterology, Washington University in St. Louis School of Medicine, St. Louis, MO.Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.