transudate transudate transudate is extravascular fluid with low protein content and a low specific gravity (< 1.012). it has low nucleated cell counts (less than 500 to 1000 /microliter) and the primary cell types are mononuclear cells: macrophages, lymphocytes and mesothelial cells. for instance, an ultrafiltrate of blood plasma is transudate. it results from increased fluid pressures or diminished colloid oncotic forces in the plasma. transudate vs. exudate transudate vs. exudate transudateexudate main causes ↑ hydrostaticpressure, ↓ colloid osmotic pressure inflammation-increased vascular permeability appearanceclearcloudy specific gravity< 1.012> 1.020 protein content< 2.5 g/dl> 2.9 g/dl fluid protein/ serum protein< 0.5> 0.5 saag = serum - effusion > 1.2 g/dl< 1.2 g/dl fluid ldhupper limit for serum< 0.6 or < 2⁄3> 0.6 or > 2⁄3 cholesterol content< 45 mg/dl> 45 radiodensity on ct scan2 to 15 hu4 to 33 hu