| Subject | Contents |
| Definition | The abdomen (peritoneal cavity) usually contains minimal fluid. In certain conditions, fluid can accumulate in the abdomen. The abdominal tap is a procedure in which a needle is inserted through the abdominal wall to obtain a sample of any fluid that is present. The sample is then sent to the laboratory for analysis. |
| Alternative Names | Peritoneal tap; Paracentesis |
| How the test is performed | This test may be done in an office, treatment room, or the hospital. The puncture site will be cleansed and shaved if necessary. You then receive a local anesthetic. The tap needle is inserted 1 to 2 inches into the abdomen. Sometimes a small incision is made to help insert the needle. The sample of fluid is then withdrawn into a syringe.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, 1 or 2 stitches are used to close it. |
| How to prepare for the test | Inform your health care provider if you have any allergies to medications or anesthetic, are taking any medications, have any bleeding problems, or might be pregnant . Infants and children: The physical and psychological preparation you can provide for this or any test or procedure depends on your child's age, interests, previous experience, and level of trust. For specific information regarding how you can prepare your child, see the following topics as they correspond to your child's age:infant test or procedure preparation (birth to 1 year) toddler test or procedure preparation (1 to 3 years) preschooler test or procedure preparation (3 to 6 years) schoolage test or procedure preparation (6 to 12 years) adolescent test or procedure preparation (12 to 18 years) |
| How the test will feel | There is a stinging sensation from the anesthetic. There is a feeling of 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 If a large amount of fluid is withdrawn, you may experience dizziness or lightheadedness .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 | The laboratory analysis will help determine why fluid is present in the abdomen. The test is frequently performed to check for internal bleeding . |
| Normal Values | There is little or no fluid in the abdomen. |
| What abnormal results mean | The presence of a bloody fluid after an injury suggests internal loss of blood. Other findings may indicate an infection; a tumor (cancerous and non-cancerous); appendicitis ; cirrhosis of the liver ; a disease of the pancreas, kidneys, or heart; and a damaged bowel. |
| 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 . There is also a slight chance of infection. |
| Special considerations | Not applicable. |
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