Why do I need a paracentesis?

Your doctor has found that you have fluid in your abdomen (ascites). We do a paracentesis to find out why fluid is building up within the abdomen. By placing a needle or thin, plastic tube into the stomach region, we can remove a small sample of fluid for testing. This sample helps the doctor to figure out what may be causing the fluid build-up. 

If there is excess fluid in a patient’s abdomen, the doctor may also remove some of it. This is very helpful if there is so much fluid that a patient is in pain or having trouble breathing. 

There are common reasons for doing a paracentesis. They include:

  • Recent fluid build-up with no clear cause.

  • To help diagnose an infection.

  • To help diagnose cancer.

  • To remove fluid and help the patient breathe with less effort.


Some of the risks include:

  • Pain – Patients may feel a poke as the doctor inserts the needle into the stomach region. Numbing drugs are used to lessen the pain. Once the needle is in, the pain is often mild and goes away.

  • Bleeding – When the doctor inserts the needle, there is a risk of piercing a blood vessel. If this happens, the bleeding is often minor and stops on its own. Patients may notice a bruise.

  • Bowel injury (perforation) – Rarely, the needle punctures the bowel. Most often, the small hole seals over quickly by itself. If not, the bowel contents can spill into the abdomen and cause an infection. In this case, patients may need surgery.

What to Expect After the Procedure

After the numbing medicine wears off, you may feel some pain at the site. You can to return to your normal routine, as you feel able.