Paracentesis is a medical procedure that doctors perform to drain fluid from a person’s abdominal cavity. It is sometimes called an abdominal tap.

Doctors refer to this buildup of fluid as ascites, and it can be a sign of an underlying condition.

It is a common complication of cirrhosis, but people with heart disease, kidney failure, certain types of cancer, and some infections may also experience it.

As draining the fluid relieves any pressure on the person’s abdominal organs, doctors may recommend paracentesis as a treatment. They may also carry out the procedure to help them diagnose the underlying condition responsible for this symptom.

Keep reading to learn what to expect from paracentesis, how to prepare, the possible risks, and more.

Paracentesis is a procedure in which a doctor inserts a needle or a thin tube called a catheter into a person’s abdominal cavity to drain excess fluid.

People usually experience immediate relief from their symptoms during the treatment.

Sometimes, the doctor may use a syringe to collect a small sample of the fluid to assist with diagnosis.

Doctors usually use paracentesis for the treatment of ascites. They may also use it for diagnostic purposes.

Treating ascites

Ascites is a condition in which fluid collects in the abdomen. A membrane called the peritoneum surrounds all of the organs in a person’s belly.

Research suggests that people usually have 50–75 milliliters of fluid inside the peritoneum. The fluid lubricates the internal organs.

If the fluid builds up, it can press on other organs. A person may feel bloated, and their stomach may expand and distend. They may also experience shortness of breath if the fluid interferes with the diaphragm.

Removing the fluid immediately relieves the pressure on the organs, but it is not a cure. Ascites may come back.


Doctors may also use paracentesis to identify the cause of ascites or to rule out certain health conditions.

If a person has ascites alongside abdominal pain, fever, or gastrointestinal bleeding, there may be a more serious underlying condition, such as kidney or liver failure, infection, or sepsis.

Doctors may recommend an ultrasound to identify the best site for the procedure. This imaging test can help them confirm the location of the ascites and assess how much fluid they need to drain.

The Memorial Sloan Kettering Cancer Center (MSKCC) explains that people may need to stop taking some medications before a paracentesis.

The organization advises people to tell the healthcare team about everything they are taking, including prescription and over-the-counter medications, herbal supplements, patches, and even creams.

Healthcare professionals will also provide specific advice on what is suitable to eat and drink before the procedure and what to avoid.

Most people undergo paracentesis in a hospital.

Immediately before the procedure, a doctor may ask the person to visit the bathroom and urinate to empty their bladder.

After the person lies on their back on the procedure table, doctors clean the abdominal area with antiseptic and then numb it with a local anesthetic. The person will be awake during the procedure.

Once the anesthetic is working, the doctor inserts a needle into the person’s abdominal cavity. If the doctor is using a catheter, they may start with a small nick in the skin to make enough room for the tubing.

If the doctor is only collecting a small sample of fluid, they will use a syringe at this point. If they are draining a larger amount, they will connect the catheter to a collection bottle.

Depending on how much fluid is present, the procedure can last up to 45 minutes. When it is complete, the doctor will remove the catheter or needle and apply pressure to the insertion site to stop any bleeding.

Throughout the procedure, other healthcare professionals will monitor the person’s blood pressure and check for any unexpected bleeding or fluid leakage.

After the procedure, a person should stay in the same position and rest for a short time.

Medical professionals will then dress the puncture site with a bandage, as it may continue to leak small amounts of fluid.

The MSKCC notes that some people experience discomfort after paracentesis and that doctors might suggest taking acetaminophen or ibuprofen.

Doctors usually recommend keeping the bandage on for 24 hours. If the puncture site is still leaking after this time, it is important to let a doctor know.

Most people can resume their normal activities after paracentesis, but it is best to check this with the doctor who performed the procedure.

Although paracentesis is generally safe, there are some risks, which a doctor will explain before the procedure.

Sometimes, fluid continues to leak from the initial puncture site. Doctors can usually stop this by stitching the wound.

When doctors remove large volumes of fluid, there is a risk that the person’s blood pressure will drop. Healthcare professionals will constantly monitor a person’s blood pressure during paracentesis to check that it does not get too low.

There is a chance of infection in the wound after the procedure. If this occurs, a person might experience fever and inflammation at the puncture site. They should contact a doctor as soon as possible if this happens.

There is also a slight risk that doctors may pierce other organs in the abdomen while inserting the needle. However, this is extremely rare.

Ascites can be an indication of a more serious condition.

Due to this, doctors may use paracentesis to diagnose certain other conditions, such as cancer, cirrhosis, kidney failure, infection, and sepsis.

Researchers estimate that as many as 80% of people in the United States with ascites have cirrhosis. The buildup of fluid is usually a sign that the person’s disease is progressing.

The National Cancer Institute notes that the accumulated fluid may contain cancer cells, especially in people with late stage cancer.

By retrieving a sample of the fluid and sending it to a lab for analysis, a doctor can rule out or confirm any of these conditions.

Doctors may send samples of the fluid to a laboratory for testing.

A doctor will likely book a follow-up appointment after the procedure to explain the results to the person and answer their questions.

If the tests reveal an underlying condition, the doctor will likely start treatment right away. They will let the person know their treatment options and outlook, which will depend on the underlying condition.

Most people with ascites experience immediate relief from their symptoms following paracentesis.

However, paracentesis is a treatment, not a cure. A person’s outlook will depend on the underlying cause of ascites.

Ascites can be a sign that a person’s disease is progressing, particularly if the person has cirrhosis or cancer.

This section answers some common questions about paracentesis.

What is the best body position when undergoing paracentesis?

Doctors usually ask people to lie on their back during paracentesis.

Depending on where the fluid is in the abdominal cavity, they might ask a person to move slightly to one side to help the liquid drain.

How much fluid should be removed during paracentesis?

If doctors recommend paracentesis to help them diagnose a person’s illness, they may only remove a small volume of fluid using a syringe.

If the procedure is for therapeutic reasons, they will remove as much as possible during the procedure.

A 2022 case study reports on a procedure in which doctors drained 29 liters of fluid over 5 hours, but this is unusual.

How much does paracentesis cost?

In 2022, for people with Medicare, a paracentesis costs about $100–200.

However, these costs do not include physician’s fees.

Some other health insurance packages may also contribute to or cover the costs of the procedure.

The out-of-pocket costs may be more. A person should discuss the cost with a healthcare professional. If they are unable to afford the procedure, there may be ways to get help with the costs.

Paracentesis is a procedure that drains excess fluid from a person’s abdominal cavity.

Fluid can build up because of an underlying condition, such as cirrhosis, some cancers, or an infection.

Doctors may use the procedure as a diagnostic tool or a treatment.