Among the first commercial instruments designed to use a fluorescence polarization immunoassay for clinical diagnostic purposes was the Abbott TDx – introduced in 1981.
The basic principle of a polarization immunoassay is to:
(1)Add a fluorescent analog of a target molecule – e.g., a drug – to a solution containing antibody to the target molecule
(2) Measure the fluorescence polarization, which corresponds to the fluorophore bound to the antibody
(3) Add the appropriate biological fluid, e.g., blood, urine, etc., and measure the decrease in polarization as the target molecules in the sample fluid bind to the antibodies, displacing the fluoroescent analogs.
FPIA – Fluorescence Polarization ImmunoAssay
Polarization ImmunoAssay