Immunoassay

Abstract

Immunoassays are still widely used for presumptive testing in forensic toxicology applications, including workplace drug testing, human performance, and medicolegal investigations. Although they cannot be used quantitatively or definitively to identify a specific substance in a forensic setting, they are widely used for screening purposes. The nature of the antibody-antigen interaction, antibody production, specificity, and cross-reactivity are described. Homogeneous and heterogeneous immunoassays are also discussed, together with the relative advantages and disadvantages of each.