Definition

An abdominal tap is a procedure in which a needle is inserted through the skin to remove fluid from the abdomen. Normally, the abdomen contains only a small amount of fluid. In certain conditions, large amounts of fluid can accumulate in the abdomen.

Alternative Names

Peritoneal tap; Paracentesis

How the test is performed

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

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 The fluid is then withdrawn into a syringe.

The needle is removed, and a dressing is applied to the puncture site. If an incision 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, or 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:

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If a large amount of fluid is withdrawn, you may experience dizziness or lightheadedness. Tell the health care provider if you feel dizzy.

Why the test is performed

An abdominal tap may be done to diagnose the cause of fluid accumulation. 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 reveal:

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.

Special considerations

Images

Digestive system
Peritoneal sample

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