Friday, May 15, 2015

A Brief Introduction of ELISA

The enzyme-linked immunosorbent assay (ELISA) is a common laboratory technique used to measure the concentration of an antibody or antigen in solution. ELISA is designed for detecting and quantifying substances such as peptides, proteins, antibodies and hormones. Other names, such as enzyme immunoassay (EIA), are also used to describe the this technology.

ELISAs were first developed in the early 1970s as a replacement for radioimmunoassays. Before the development of the ELISA, the only option for conducting an immunoassay was radioimmunoassay. Radioactivity have potential health threat, and so later ELISA was developed as a safer alternative to replace the use of radioimmunoassay. 

An ELISA involves at least one antibody with specificity for a particular antigen. In an ELISA, an antigen must be immobilized to a solid surface and then complexed with an antibody that is linked to an enzyme. The antigen of interest can be immobilized by direct adsorption to the assay plate or by first attaching a capture antibody to the plate surface. Detection is achieved by assessing the conjugated enzyme activity via incubation with a substrate to produce a measureable product. The most crucial element of the detection strategy is a highly specific antibody-antigen interaction.

An ELISA has also been commonly performed as a competitive assay, when the antigen is small and has only one epitope, or antibody binding site. One variation of this method consists of labeling purified antigen instead of the antibody. Unlabeled antigen from samples and the labeled antigen compete for binding to the capture antibody. A decrease in signal from purified antigen indicates the presence of the antigen in samples when compared to assay wells with labeled antigen alone.

Creative Diagnostics provides contract ELISA development kit services for the R&D and IVD community. We conduct ELISA kit development services for supporting regulatory approval submission. Creative Diagnostics will carry out the approval proposal and deliver the expected results and documents in a time and cost effective manner.



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