What is paracentesis?

Paracentesis is the process of draining fluid from an bone or other organ through a hollow needle.

Paracentesis is a procedure for removing fluid from a body cavity or a cyst with a hollow needle or catheter. Paracentesis commonly refers to peritoneocentesis, which is removal of fluid from the abdominal (peritoneal) cavity. Paracentesis of the chest cavity is known as thoracentesis.

What is abdominal paracentesis?

An abdominal paracentesis is a procedure done to remove fluid from the abdominal cavity. This may be a sample removal for testing purposes or a treatment for patients who have fluid in the abdomen (ascites).

What is ascites?

Ascites is a condition in which excessive fluid collects in the patient’s abdominal cavity, causing symptoms including:

Ascites is usually a result of pressure buildup in the veins of the liver. When the liver is unable to function normally, the kidneys can’t flush excess salt and fluid. As a result, fluid builds up in the abdominal cavity. 

Ascites may be caused by

Why would someone need a paracentesis?

Paracentesis may be performed for diagnostic or therapeutic purposes. It is usually considered when treatment with diuretics -- known as water pills -- that flush out the fluid, and restriction in fluid and salt intake do not stop the fluid buildup. Some patients may need repeated fluid draining.

Fluid is removed for diagnosis in patients with:

  • New-onset ascites to determine the cause
  • Suspected bacterial peritonitis
  • Refractory ascites, or ascites that recurs despite treatment
  • Paracentesis is performed as a treatment when ascites induces
  • Impaired breathing
  • Abdominal pain or pressure

Paracentesis is avoided in patients with:

  • An acute abdomen that requires surgery
  • Low blood platelet count (thrombocytopenia)
  • Bleeding or clotting disorders
  • It has to be done with extra caution in certain situations such as:
  • Pregnancy
  • Distended bowel or bladder
  • Adhesions from previous surgery
  • Cellulitis in the abdominal wall


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How long does a paracentesis take?

A paracentesis usually takes about 30 minutes to complete. If a large amount of fluid needs to be drained, it might take longer.

How is a paracentesis done?

A gastroenterologist usually performs a paracentesis as an outpatient procedure. People with refractory ascites or severe complications from the underlying disease are likely to be hospitalized.


  • The doctor goes through the medical history of the patient and evaluates them physically.
  • The patient undergoes blood and imaging tests.
  • The patient must inform the doctor of any allergies or regular medications taken.
  • The patient’s bladder is emptied with a catheter, if necessary.


  • The entry point is usually at the midline of the stomach, 2 cm below the navel, or 5 cm from the navel on either side of the stomach.
  • Doctors use ultrasonography to select the entry site and insert the needle, avoiding blood vessels and abdominal organs.
  • The doctor numbs the stomach wall with local anesthesia.
  • The doctor makes a tiny incision in the skin.
  • The doctor then inserts a hollow needle with a syringe till fluid starts appearing in the syringe.
  • The doctor will fill vials with samples for testing, or insert a catheter and drain the excess fluid.
  • After the procedure the puncture site is closed with a bandage.
  • Typically patients are under observation for about 30 minutes and given painkillers as needed.
  • The patient may require a low-fluid and low-salt diet.

Does paracentesis hurt?

The anesthetic injection might cause a brief sting, and there might be a little pain or pressure when the catheter is inserted.

What are the risks of paracentesis?

Paracentesis is generally a safe procedure, life-saving in some. There are some associated risks and complications, depending on the patient’s condition also to some extent. The risks may include:

  • Failure in attempt to collect or drain fluid
  • Infection at the puncture site
  • Dizziness when large volume of fluid is removed
  • Persistent leak from the puncture site
  • Hematoma in the abdominal wall
  • Injury to stomach, bladder or intestines
  • Injury to blood vessels and bleeding
  • Low blood pressure and low sodium
  • Kidney failure


Long-term heavy alcohol consumption can cause: See Answer

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Medically Reviewed on 3/23/2020
Medscape Reference