Fluorescence polarization immunoassay. iii. an automated system for therapeutic drug determination.

A fully automated system for performing fluorescence polarization immunoassay has been developed. Reagents for each assay are contained in coded reagent packs, and no reagent reconstitution is required. A common buffer is used for all assays, minimizing changeover and set-up times for each assay. A single sample may be assayed in 5 min, or 20 samples in 10 min. A single-tube blank subtraction for each sample results in highly precise polarization values and obviates sample interferences. We have used this method for assays of gentamicin, theophylline, phenytoin, and phenobarbital. CVs are 1-4%, and the results correlate well with those by other methods. Because of the instrument design and the stability of the reagents, daily calibration is not required; samples may therefore be run immediately upon receipt or batched as desired.