ELISA - ELISA TYPES (Jun/27/2005 )
i want to know what exactly is the difference between 1st,2nd and 3rd generation ELISAs.
As far as I know, the assay protocol is basically the same. The differences are in the sensitivity (e.g. using higher titer antibodies), specificity (e.g. polyclonal vs. monoclonal), and selection of antibodies recognizing epitopes that are more conserved in all strains of the protein/pathogen to be detected.
Thus the 1st, 2nd and 3rd generation assays for detection of different diseases such as HIV, HCV, EBV are different from each other. For specific answer you'll have to look at the assays for the particular disease of your interest.
In immunoassay the "generations" referred to the levels of sensitivity of the assay. Example TSH---IU/ml; mIU/ml; uIU/m. I believe TSH is now 3rd generation assay.