Quinidine, Serum

Method Description

The assay is a homogeneous immunoassay based on the principle of measuring changes in scattered light or absorbance, which result when activated microparticles aggregate. The microparticles are coated with quinidine and rapidlyaggregate in the presence of a quinidine antibody solution. When a sample containing quinidine is introduced, the aggregation reaction is partially inhibited, slowing the rate of the aggregation process. Antibody bound to sample drug is no longer available to promote microparticle aggregation, and subsequent particle lattice formation is inhibited. Thus, a classic inhibition curve with respect to quinidine concentration is obtained, with the maximum rate of aggregation at the lowest quinidine concentration. By monitoring the change in scattered light or absorbance, a concentration-dependent curve is obtained.(Package insert: Roche Quinidine reagent, Roche Diagnostic Corp, Indianapolis, IN)