Immunochemical techniques in biological monitoring

Immunoassays are analytical methods that detect interactions between antibodies and antigens. Immunoassays were used originally to detect large biological molecules. The new generation of these antibody-based assays can detect small synthetic compounds. As a result, immunoassays are being developed specifically for biomarkers of exposure and effect to environmentally prevalent chemicals. Immunochemical detection of parent compounds in blood and tissues, metabolites in excreta, and adducts with DNA and protein have been successfully performed by several investigators. Although there is great potential for use of immunoassays in biological monitoring studies, the limitations of these analyses must be fully understood to prevent improper evaluation of the acquired data. This review will cover some of the background material necessary to understand how an antibody-based assay is developed. The differences between polyclonal and monoclonal antibody-based assays and the importance of antibody class, affinity, specificity, and cross-reactivity must be considered in both study design and data analysis.