The determination of antithrombin III, alpha 2-macroglobulin and alpha 2-antiplasmin in plasma by laser nephelometry

Specific assay procedures were developed to determine antithrombin III, alpha 2-macroglobulin, and alpha 2-antiplasmin in plasma with the aid of a Laser nephelometer. About 100 normal and pathological plasmas were examined and the results compared with those obtained by conventional immunological methods, such as radial immunodiffusion or rocket electrophoresis. Nephelometry proved to be a very rapid, precise, and reproducible method for the determination of antithrombin III and alpha 2-macroglobulin. The reproducibility of the alpha 2-antiplasmin assay was poor, probably as a consequence of the low concentration of this inhibitor in normal plasma.