Modified Transudates

A modified transudate is a transudate that has been modified by the presence of additional protein, cells, or both. Guidelines for modified transudates are the most variable in the veterinary literature. When the two values are incongruous (protein above transudate limits but nucleated cell count within transudate limits, or protein within transudate limits but nucleated cell count above transudate limits), the fluid is correctly termed a modified transudate. Fluids with protein concentration and nucleated cell count which are both above the limits for transudate, but not as high as an exudate, would also be classified as modified transudate. A general guideline for defining a modified transudate is basically a fluid that is neither a transudate nor an exudate: either the protein is >25 g/L (with nucleated cell count of <7 x 10⁹/L) or the nucleated cell count is >1.5 x 10⁹/L (with protein content of <30 g/L), or the protein is 25-30 g/L and the nucleated cell count is >1.5 to 7 x 10⁹/L.

The most common causes of modified transudates are cardiac disease (such as congestive heart failure and cardiomyopathy), exfoliating neoplasms, and chylous effusions (early stage).