Exudate

A fluid rich in protein and cellular elements that oozes out of blood vessels due to inflammation and is deposited in nearby tissues. 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. By comparison, a transudate is a fluid that passes through a membrane which filters out much of the protein and cellular elements and yields a watery solution. The process of transudatation is due to increased pressure in the veins and capillaries pressure forcing fluid through the vessel walls or low levels of protein in the serum. The transudate is a filtrate of blood.

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Any fluid that has exuded out of a tissue or its capillaries, more specifically because of injury or inflammation ( e.g., peritoneal pus in peritonitis, or the e. that forms a scab over a skin abrasion) in which case it is characteristically high in protein and white blood cells. Cf.:transudate. SYN: exudation (2). [L. ex, out, + sudo, to sweat]

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ex·u·date 'ek-s(y)u̇-.dāt, -shu̇- n exuded matter esp the material composed of serum, fibrin, and white blood cells that escapes from blood vessels into a superficial lesion or area of inflammation

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ex·u·date (eksґu-dāt) [L. exsudare to sweat out] material, such as fluid, cells, or cellular debris, which has escaped from blood vessels and has been deposited in tissues or on tissue surfaces, usually as a result of inflammation. An exudate, in contrast to a transudate, is characterized by a high content of protein, cells, or solid materials derived from cells.