Definition and Overview

Paracentesis, derived from the Greek word that means “to pierce,” is a procedure that involves puncturing the abdomen to collect peritoneal fluid. This accumulation of fluid in the abdominal area is known as ascites, which can be caused by a variety of reasons, including cancer, injury, infection, cirrhosis, or inflammation. Paracentesis is usually performed to collect samples, in which the collected fluid is sent to a laboratory for further testing. However, it can also be performed to drain peritoneal fluid and provide relief (from pressure) for patients with cancer or cirrhosis.

There are generally two kinds of paracentesis; diagnostic paracentesis, which is performed to diagnose serious conditions such as liver diseases and cancers and large volume paracentesis, which is performed to drain significant amount of fluid from the abdominal cavity.

Who Should Undergo and Expected Results

This procedure is recommended for patients with ascites, a condition that involves the accumulation of fluid in the peritoneal cavity in the abdomen, and is quite common in patients with severe liver disease, cirrhosis, or cancer that has metastasized to the organs in the abdomen.

Patients with severe ascites tend to have distended stomachs because of all the fluid that has accumulated in the peritoneal cavity. The fluid builds up in the abdominal lining and organs, which can cause uncomfortable, and sometimes painful, pressure in the abdominal area. Patients with ascites can experience shortness of breath and bowel problems due to this pressure.

Aside from the peritoneal cavity, paracentesis can be performed in other parts of the body such as the ears or eyes.

There are a number of reasons for a paracentesis procedure to be performed, including the following:

  • Diagnosis of metastatic cancers
  • Determining the presence of infections, such as spontaneous bacterial peritonitis
  • Relieving abdominal pressure caused by ascites
  • Collecting blood in the peritoneal cavity in the event of trauma or injury
  • Puncturing the tympanic membrane to determine the cause of excessive gas accumulation in the gastrointestinal tract
  • Determining the extent of damage in the abdominal area in the event of illness or injury
  • Collecting samples to test for bacteria in the ear
  • Relieving pressure in the retina

If the paracentesis procedure is performed to relieve or reduce pressure caused by gas or fluid build-up, the patient is expected to experience relief from the symptoms he or she is suffering from.

How is the Procedure Performed?

Before a paracentesis procedure can be performed, the patient must first inform the doctor of the following:

  • The kind of medication he is currently taking
  • Any allergies to anaesthetics
  • Have experienced problems with bleeding or blood clotting in the past
  • For female patients, if they are currently pregnant or might be pregnant

The doctor will perform other tests before the actual paracentesis to ensure that the patient does not have any conditions that might aggravate the procedure, such as blood clotting problems. The patient will also be asked to empty his or her bladder prior to the procedure.

Paracentesis is typically performed in an outpatient clinic or at a doctor’s office, but it can also be performed in an emergency room in a hospital. Only trained medical professionals should perform this sensitive procedure to avoid serious risks and complications.

The patient will need to lie on a bed, with his or her head elevated to ensure that the fluid accumulates in the lower abdomen. Typically, the doctor will apply a topical or local anesthetic on the site where the needle will go in.

Diagnostic paracentesis only requires a small amount of peritoneal fluid. This sample will be sent to a laboratory for further testing, and the results will be sent back to the diagnosing physician for analysis.

In a large volume paracentesis procedure, the doctor will need more time to drain the fluid and a vacuum bottle, which is attached to the needle, will be used to aid in the draining. If the patient has severe ascites, he or she might need to sit through several sessions to ensure that all the fluid in the abdomen is completely drained.

After the procedure, the doctor will apply dressing to the site of the puncture.

Diagnostic paracentesis typically takes 30 minutes. However, draining large amounts of fluid will take more time. The patient can resume normal activities a couple of hours after the procedure if blood pressure is normal.

Possible Risks and Complications

If performed by a qualified and trained medical professional, paracentesis does not typically lead to serious risks and complications. However, people who have taken blood-thinning medication or have bleeding problems might experience serious complications such as internal or continuous bleeding. There is also a small risk of infection and the chance of the needle perforating a vital organ in the abdomen, such as the bowels.


  • Garcia-Tiso G. Cirrhosis and its sequelae. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 156.

  • Runyon BA. Ascites and spontaneous bacterial peritonitis. In: Feldman M, Friedman LS, Sleisenger MH, eds. Sleisenger & Fordtran's Gastrointestinal and Liver Disease. 9th ed. Philadelphia, PA: Elsevier Saunders; 2010:chap 91.

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