Immunoassay of Steroids

Prior to 1970, few chemical methods existed that were appropriate for the determination of nanomolar and picomolar concentrations of steroid hormones in biological fluids. Nevertheless, by the end of the 1960s, several technologies were being proposed for the measurement of steroids in serum and urine, which included gas–liquid chromatography (Collins et al., 1968), double isotope derivatization (Kliman and Peterson, 1960; Gandy and Peterson, 1968), spectrophotometry and fluorometry (Brown et al., 1968).