Biochemical analysis of pleural, peritoneal and pericardial effusions.

Body fluids other than blood, urine and cerebrospinal fluid are often submitted for biochemical analysis. Of these, pleural, peritoneal and pericardial fluids are the most common. Laboratory tests are a useful tool to assess the aetiology, pathophysiology and subsequent treatment of effusions. A wide range of biochemical tests may be requested. This review critically examines the various analytes that have been used to investigate these body fluids.