Enzyme linked immunosorbent assays calibration curves

Figure 3. Calibration curves for E.coli 0157 H7 enzyme immunoassay using the immunofiltration assay system with amperometric detection (a) and an enzyme-linked immunosorbent assay (ELISA) (b) with spectrophotometric detection.

The enzyme-linked immunosorbent assay (ELISA or EIA) is one of the most commonly utilized methods used in protein detection and analysis. An ELISA can provide quantitative information about antigen or antibody concentrations in solution by comparing the results of an unknown sample assay to a calibration curve based on known standard concentrations of the antibody or antigen of interest. Although, there are many variations in how ELISA may be performed, three of the most commonly used representative methods are discussed here (Fig. 1). The choice of which ELISA technique is used often depends on the nature of the antigen or antibody of interest, the availability of appropriate binding pairs, and the specificity of only the antigen of interest to a monoclonal antibody. 

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