The ELISA method is a benchmark for quantitation of pathological antigens and there are indeed many variations to this method. ELISAs are adaptable to high-throughput screening because results are rapid, consistent and relatively easy to analyze. The best results have been obtained with the sandwich format, utilizing highly purified, prematched capture and detector antibodies. The resulting signal provides data which is very sensitive and highly specific.
A chemical compound with which an enzyme reacts specifically. This reaction is used, in some way, to produce a signal that is read as a color reaction (directly as a color change of the substrate or indirectly by its effect on another chemical).