Dr York Cheung
Dr James Burnes

What is an ascitic tap?

An ascitic tap is a medical procedure where a needle is used to drain fluid that is trapped in an internal body cavity, most commonly the abdomen (belly). Fluid may have to be drained from the abdomen for different reasons, such as if the fluid is stretching the abdomen and causing pain; if the fluid is infected; or if a doctor needs to analyse the fluid in a laboratory for the presence of any disease.

A radiologist (specialist doctor) uses ultrasound to show images or pictures of the inside of the abdomen on a screen to guide the needle to where the fluid is situated.

Other names for an ascitic tap are ‘abdominocentesis’, ‘paracentesis of the abdomen’ or ‘ascitic drain’.

How do I prepare for an ascitic tap?

You may be asked to fast (not to eat or drink for a period of time) before having the procedure. This is very important as your intestines (or bowel) move involuntarily after you eat, which can make the ascitic tap more difficult to carry out.

If you are taking warfarin (Coumadin or Marevan) or other blood thinning medications, you will need to stop taking it for several days before having the ascitic tap. This period can range from 5 days to 10 days if you are taking Clopidogrel/Asasantin. Your referring doctor will advise you about this. If the risks of not taking these medications are considered too high, such as if you have recently had stents inserted or other cardiac (heart) procedures, this should be discussed with your referring doctor and the radiologist carrying out the procedure before having the procedure done. Alternate blood thinning medications may be necessary. If you are taking warfarin, an INR (this is the blood test you have regularly to check that your warfarin dose is appropriate) is required before the procedure, preferably on the same day. Aspirin does not need to be stopped before you have the procedure.

Special blood tests are recommended for all patients with liver disease. Your referring doctor will arrange this before you have the ascitic tap.

What happens during an ascitic tap?

You will be asked to lie on your back on a bed and your abdomen will be wiped clean with antiseptic liquid.

The doctor will locate the fluid in your abdomen and determine the easiest way to reach the fluid by using ultrasound images that show the inside of your abdomen on a screen.

You will be fully awake during the whole procedure, but the doctor will numb a small area of skin with local anaesthetic for your comfort. Through the numb patch of skin, a needle is used to insert a thin plastic drain tube into the area of fluid. This allows the fluid to drain out of the body into a sealed plastic bag. Once enough fluid has been removed, the tube is carefully removed by a nurse or doctor. This only takes a couple of seconds and no stitches are required. You will then be allowed to go home.

Are there any after effects of an ascitic tap?

Usually, you will feel as you did before the ascitic tap, with no after effects. If there has been a lot of fluid in your abdomen and this has been removed, you may feel much more comfortable than before.

If you have had a lot of fluid drained, it can lower your blood pressure and make you feel dizzy or lightheaded. Occasionally, the doctor may give replacement fluids into your veins to reduce this side-effect.

Once most of the fluid drains out from your abdomen, the tubing can be uncomfortable or even painful. This is usually relieved once the drain tube is removed.

Most patients will have a very tiny (3 mm) scar on the skin at the site where the drain tube was inserted. After the procedure is finished, the entry site will be covered with a waterproof dressing so you may have a shower. You should avoid swimming or any strenuous activities for at least 5 days while the wound fully heals.

Occasionally, fluid may continue leaking out of the wound under the dressing. It is important to keep the wound clean and covered with a dressing until it is dry and is no longer oozing any fluid.

How long does an ascitic tap take?

The whole procedure, including ultrasound scanning to locate the fluid, setting up the instruments and placing the tube into position, can take between 15 to 30 minutes.

Once the drain tube is in place, you will have to wait for the fluid to drain. This may take from 5 minutes to several hours, depending on the amount of fluid and how fast it drains.

You will be allowed to go home once the fluid has drained out and the drain tube has been removed.

What are the risks of an ascitic tap?

This procedure is low risk.

  • The risk of introducing infection into your abdomen or the skin wound is also very low. Many measures are taken by the doctor to minimise this risk.
  • There is a small risk that you will continue to drain fluid from the puncture site for many days after the procedure.
  • Bleeding is a rare complication
  • Damage to adjacent organs is very rare due to the use of an ultrasound machine to guide the procedure.
  • If a lot of fluid is removed, you may be dizzy due to low blood pressure. Sometimes this might require intravenous fluids.

Inform your doctor immediately if you develop a fever, severe pain, redness at the wound site, blood in your urine or bleeding from the site.

What are the benefits of an ascitic tap?

An ascitic tap allows fluid in the abdomen to be removed if it is infected, causing pain or if it requires laboratory analysis to diagnose a disease. An ascitic tap is quicker, easier and safer than other methods that can be used to remove fluid from the abdomen. It also leaves a smaller scar and allows for quicker recovery afterwards.

Occasionally, if the fluid is too deep to reach through the skin or if there are too many separate pockets of fluid, it may be decided an ascitic tap should not be used. This can only be determined at the time of the procedure, when the doctor uses ultrasound images to locate the fluid and is able to assess the best method to use for drainage.

Who does the ascitic tap?

Ascitic tap procedures are only carried out by specialist doctors, usually radiologists. The specialist doctor will provide a written report to your referring doctor.

There are usually two staff members in the room with you during the procedure: the doctor who will carry out the procedure and the nurse who will help to look after you. Occasionally, a sonographer may be present to operate the ultrasound machine.

Where is an ascitic tap done?

An ascitic tap is carried out in most hospitals, medical day centres and private radiology practices. It is not usually carried out at general practice clinics.

When can I expect the results of my ascitic tap?

The time that it takes your doctor to receive a written report on the test or procedure you have had will vary, depending on:

  • the urgency with which the result is needed;
  • the type of laboratory tests that need to be carried out on a sample of the fluid;
  • whether more information is needed from your doctor before the examination can be interpreted by the radiologist;
  • how the report is communicated to your doctor (i.e. phone, email, fax or mail) .

Please feel free to ask the staff where you are having your test or procedure done when your doctor is likely to have the written report.

It is important that you discuss the results with the doctor who referred you, either in person or on the telephone, so that they can explain what the results mean for you.

Last saved on 26 September 2016.