Indirect competition enzyme-linked immunosorbent assay

Indirect competitive enzyme-linked immunosorbent assay... 

Pinacho, D.G., F. Sanchez-Baeza, and M.P. Marco. 2009. Development of a class selective indirect competitive enzyme-linked immunosorbent assay (ELISA) for detection of fluoroquinolone antibiotics. J. Agric. Food Chem. submitted. 

Yu, W., X. Zhen-Lin, X. Yan-Yun et al. 2011. Development of polyclonal antibody-based indirect competitive enzyme-linked immunosorbent assay for sodium saccharin residue in food samples. Food Chem. 126 815-820. 

Competitive enzyme-linked immunosorbent assays (ELISA) Two types of ELISA have been used for the analysis of mycotoxins and both types are heterogenous competitive assays. One type, i.e. direct ELISA, involves the use of a mycotoxin-enzyme conjugate and the other system, i.e. indirect ELISA, involves the use of a protein-mycotoxin conjugate and a secondary antibody to which an enzyme has been conjugated. Although horseradish peroxidase (HRP) is most commonly used as the enzyme for conjugation, other enzymes such as alkaline phosphatase and beta-galactosidase, also have been used (5, 9, 13). 

Immunoassays vary by the different labels they use. The most common labels include chromophores, fluorophores, radioisotopes and enzymes. Of those labels, enzyme immunoassay or enzyme-linked immunosorbent assay (ELISA) is the most popular technique. ELISA has as an advantage the amplification of the analytical signal and/or increase of the sensitivity of the immunoassay. There are four types of ELISA direct ELISA, indirect ELISA, sandwich ELISA and competitive ELISA. 

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