Radioimmunoassay was the only way to perform an immunoassay until the discovery of ELISA, it used the antigens and/or antibodies that are radioactive, as they provide a sort of a signal that informs if the substance (antigen/antibody) is in the sample, later when radioactivity was realiszed to be a health possible problem, thinking of alternative method that is safer was begun. The first idea came from the fact that enzymes can perform a color changing...
Radioimmunoassay was the only way to perform an immunoassay until the discovery of ELISA, it used the antigens and/or antibodies that are radioactive, as they provide a sort of a signal that informs if the substance (antigen/antibody) is in the sample, later when radioactivity was realiszed to be a health possible problem, thinking of alternative method that is safer was begun. The first idea came from the fact that enzymes can perform a color changing reaction on their specific antigens or antibodies, this can help determine the presence of those in the sample, however, this method relies on the enzyme and its substrate which are very specific, therefore every antigen or antibody will be tested specifically.
Recently the ELISA have been developed using many techniques like Polymerase Chain Reaction, which enhances the ELISA in a great way also the recent use of nanoparticles as a reporter, gave a signal that can be seen visually with the naked eye, this is done by comparing the red or blue color being the negative or positive results respectively.
