Transudate

Transudate is a plasma, ultrafiltrate that does not contain large plasma proteins (e.g. fibrinogen) and contains very little or no cells. Transudate arises from increased hydrostatic pressure or decreased oncotic pressure.

Exudate, on the other hand, is a sign of inflammation and is typically a consequence of increased vascular permeability. Vascular changes allow the diapedesis of white blood cells and the passage of plasma proteins of high molecular weight. Accordingly, transudate resembles serum, while exudate resembles cell-rich plasma. Transudates do not coagulate, exudates do.

Pathology
The most common causes of pathological transudate include the following conditions:

Increased hydrostatic pressure in blood vessels: heart failure of the left ventricle

Reduced oncotic pressure in blood vessels:
 * Cirrhosis (cirrhosis leads to hypoalbuminism and a decrease in plasma oncotic pressure, which causes edema)
 * Nephrotic syndrome (also due to hypoalbuminemia due to proteinuria)
 * Malnutrition (hypoalbuminism)

Taken from
http://www.nspka.cz/NSPKA_prirucky/2012/laboratorni_prirucka_OKBH_orlova/HVEZDAABHE.htm