Magnetisable solid-phase fluoroimmunoassay of human immunoglobulin G in serum

A simple fluoroimmunoassay is described for the determination of immunoglobulin G (IgG) in serum. It employs IgG labelled with fluorescein and magnetisable polyacrolein/iron oxide particles covalently linked to goat anti-human IgG serum. Diluted patient sample or standard and fluorescein-labelled IgG are incubated for 30 min with solid-phase antibody, the antibody-bound and free antigen separated simply by means of a magnet and the fluorescence in the supernate (free fraction) determined, which directly reflects the IgG concentration of the standard or sample. Correlation studies with two other immunological methods showed good agreement.