Transudate

A fluid that passes through a membrane which filters out much of the protein and cellular elements to yield a watery solution.

A transudate is due to increased pressure in the veins and capillaries pressure forcing fluid through the vessel walls or low levels of protein the blood serum.

It is a filtrate of blood.

The transudated fluid accumulates in tissues outside the blood vessels and can cause edema (swelling).

By comparison, an exudate is a fluid rich in protein and cellular elements that oozes out of blood vessels due to inflammation and is deposited nearby.

The altered permeability of blood vessels permits the passage of large molecules and solid matter through their walls.

The vessels seem to weep, to sweat, in keeping with the Latin 'exsudare', to sweat out, from which exudate is derived.