ABSTRACT
This chapter explains the use of radioimmunoassay (RIA) for the analysis of drugs; RIA being a special case of saturation analysis. Commercial development of RIA, particularly for drugs in widespread use, means that clinical chemistry screening or monitoring laboratories are rarely faced with problem of raising their own antisera. Successful RIAs for drugs have been described using the iodine label, mainly by incorporating the label in the link in the carrier protein or in the protein itself. The heart of the RIA procedure is the incubation of the antiserum reagent, the tracer, and the unknown. For traditional RIA, it is not possible to measure the bound and unbound label directly and two fractions normally have to be separated prior to using standard counting techniques. Many separation techniques have been used including different migration methods, such as paper chromatoelectrophoresis and gel filtration, absorption methods, such as charcoal and silicates, fractional precipitation with salts or double antibody methods, and solid phase methods.
