Useful For

Pleural Fluid (Thoracentesis): There is normally about 1 to 15 mL of pleural fluid in the pleural space surrounding the lungs.  In normal conditions, there is not a true pleural space.  An abnormal accumulation of fluid (pleural effusion) in the pleural space is seen in the presence of certain diseases.

Pericardial Fluid (Pericardiocentesis): The pericardial space surrounding the heart normally contains 10-50 mL of clear, straw colored tissue fluid, an ultrafiltrate of plasma called pericardial fluid.  When an abnormal accumulation of this fluid occurs, it fills the space around the heart and can mechanically inhibit the normal activity of the heart.  Relief is obtained by aspiration of the excess fluid.

Peritoneal Fluid (Paracentesis): There is normally less than 100 mL of clear, straw colored tissue fluid present in the peritoneal space surrounding the abdominal viscera.  Large amounts of fluid can be removed to alleviate discomfort.

Synovial Fluid (Arthrocentesis):  Synovial fluid is a colorless or pale yellow, transparent, and viscous liquid found in the joint cavities. Although synovial fluid is found in all joints, the specimen frequently received in the laboratory is an aspirate of the knee.  The normal amount of fluid contained in the knee cavity is less than 3.5 mL; however, this amount increases in disorders of the joint.