Transudate versus exudate
First the fluid is either transudate or exudate.A transudate is defined as pleural fluid to serum total protein ratio of less than 0.5, pleural fluid to serum LDH ratio < 0.6, and absolute pleural fluid LDH < 200 IU or < 2/3 of the normal serum.
An exudate is any fluid that filters from the circulatory system into lesions or areas of inflammation. It can apply to plants as well as animals. Its composition varies but generally includes water and the dissolved solutes of the main circulatory fluid such as sap or blood. In the case of blood: it will contain some or all plasma proteins, white blood cells, platelets and (in the case of local vascular damage) red blood cells.
''Exudate ''
* hemorrhage
*Infection
*Inflammation
*Malignancy
*Iatrogenic
*Connective tissue disease
*Endocrine disorders
*Lymphatic disorders vs Constrictive pericarditis
''Transudate''
*Congestive heart failure
*Nephrotic syndrome
*Hypoalbuminemia
*Cirrhosis
*Atelectasis
* trapped lung
*Peritoneal dialysis
*Superior vena cava obstruction
Amylase
A high amylase level (twice the serum level or the absolute value is greater than 160 Somogy units) in the pleural fluid is indicative of either acute or chronic pancreatitis, pancreatic pseudocyst that has dissected or ruptured into the pleural space, cancer or esophageal rupture.Glucose
This is considered low if pleural fluid value is less than 50% of normal serum value. The differential diagnosis for this is:*rheumatoid effusion.The levels are characteristically low (
Adapted from the Wikipedia article Thoracentesis, under the G. N. U. Free Documentation License. Please also see http://en.wikipedia.org/wiki
