Laser nephelometric quantitation of antithrombin-III (AT-III) development of a new assay

Abstract

Antithrombin-III (AT-III) concentration in normal healthy volunteers and in an out-patient population was determined by a radial immunodiffusion (RID) and by a laser nephelometric technique, developed in our laboratory. In 43 normal individuals tested, the mean AT-III concentration by laser nephelometry was 24.1 ± 3.3 mg/dL or 108 ± 13% normal human plasma pool (NHP). The coefficient of variation (CV) of the assay was in the order of 7–10% and there was a good correlation (r=0.81) between RID and laser nephelometric method. Some developmental aspects of the laser nephelometric procedure and its advantages over the RID method are discussed.