A procedure in which a body cavity is punctured with a needle from the outside.

Paracentesis is most often performed to remove fluid for analysis to aid daanosis of medical conditions causing ascites, a reference to fluid which collects in the abdominal cavity.

Ascites can occur as a result of a number of conditions, including severe liver disease and the presence of malignant cells within the abdomen.

The paracentesis process may also be performed to relieve pressure due to excess fluid or to instill drugs.

Abdominal or thoracic paracentesis is most common; however, other sites include the pericardium and the scrotum

The procedure is usually carried out using local anesthesia and it is said to be quick and relatively painless.

1. The surgical puncture of the abdominal cavity for the removal of fluid for diagnosis or treatment: Joan had to go to the hospital to have an abdominal paracentesis performed because she had excess liquid in the visceral area.
2. A puncture of the wall of a fluid-filled cavity with a hollow needle to draw off the contents for medical diagnosis: A trocar is used during an abdominal paracentesis to obtain some ascitic fluid for examination from a patient while he or she is in a sitting position.