Simultaneous determination of alpha-fetoprotein, human chorionic gonadotropin and estriol in serum of pregnant women by time-resolved fluoroimmunoassay.

We have developed a simple and rapid time-resolved fluoroimmunoassay (TR-FIA) for simultaneous determination of alpha-fetoprotein (AFP), human chorionic gonadotropin (hCG) and estriol (E3) using europium and samarium ion chelate. In the proposed method, we used a combination of a 96-well microtiter plate for the AFP and hCG assay and transferable solid phase plate for the E3 assay. Therefore, these analytes could be measured simultaneously. The measurable ranges for AFP, hCG and E3 by the proposed method were 3.91-1000 ng ml(-1), 877-250000 IU l(-1) and 0.39 100 ng ml(-1), respectively. The proposed method which utilized characteristics of a rare earth ion chelate, was convenient (unnecessary diluting samples), quick (96 assays for 2 h), and required only a small quantity sample (50 microl). The principle of this proposed method is applicable to other antigens.