Immunochemical Analysis of Endogenous and Exogenous Estrogens

Endogenous estrogens, namely estradiol, estriol and estrone are essential substances for the sexual determination, growth and reproduction of human beings. Their levels in the human sera are important index in monitoring pregnancy, evaluating menstrual dysfunctions and diagnosing many other diseases. On the other hand, many exoestrogens, including the phytoestrogen such as isoflavones, the synthetic estrogens such as diethylstilbestrol and chemicals of industry origin with suspected estrogenic activity such as bisphenol A and 4-nonylphenol, are drawing increasing attention in recent years. This paper reviews the main immunochemical analytical methods for these important estrogenic substances. The immunizing hapten design and its influence on the specificity of produced antibody were discussed. The typical available immunoassays including enzyme immunoassay (EIA), fluoroimmunoassay (FIA) and chemiluminescence immunoassay (CLIA) for the detection of estrogens were compared with respect to their features (especially dynamic range and limit of detection). The performance of different types of immunosensors with respect to their advantages and disadvantages were evaluated. The future developing trend in this field was also briefly discussed.