Automated fluorescence polarization immunoassay

B Rollman, et al. Dibekacin assay in serum by automated fluorescence polarization immunoassay (Abbot TDX)—Comparison with high performance liquid chromatography, substrate labeled fluorescent immunoassay and radioimmunoassay. J Pharm Biomed Anal 4 53, 1986. 

The fluorescence polarization immunoassay is used for routine, automated immunoassay of small molecules, such as drugs. It depends on the principle that a fluorophore attached to a macromolecule such as an antibody is not free to rotate in solution. If polarized light is used to stimulate the fluorophore to fluoresce, emission from the bound fluorophore (attached to the antibody, which is bound to a surface) will continue to be polarized, but polarization will be lost from free fluorophore (111). 

JoUey ME, Stroupe SD, Schwenzer KS, et al. Fluorescence polarization immunoassay. III. An automated system for therapeutic drug determination. Clin Chem 1981 27 1575-9. 

Nonisotopic methods have also been described. For example, a homogeneous (nonseparation) fluorescence polarization immunoassay for DHEA-S that uses a rabbit polyclonal antibody and a DHEA-fluorescein tracer is available. The measured polarization is inversely related to DHEA-S concentration. This fully automated system has a dynamic range of 1 to lOOOjJ-g/dL (0,03 to 27 Limoi/L), and interassay coefficients of variation are less than 10% over a broad concentration interval (25 to lOOOpg/dL 0.7 to 27pmol/L). Assay time is about 15 minutes for a single sample and 30 minutes for 20 samples. 

---