Magnetic microparticle radioimmunoassay for the determination of estriol in human serum

In the present work, using the magnetic microparticle, two ultra-sensitive and simple methods based on the traditional radio-immunoassay for the determination of estriol ( E3) in serum were developed. Magnetic microparticles were used as the second-antibody separation agent and the first-antibody solid-surface blocked agent.. Under the selected conditions, the measurement calibration curve for E3 was in the range of 0. 3 - 30 mu g/L. The intra- and inter- RSD of second-antibody method was 4. 3 % and 8. 7 % respectively. The recovery was 104% - 114%, and the soundness coefficient was 0. 9989; The intra- and inter- RSD of first-antibody method was 4. 4% and 7. 6% respectively. The recovery rate was 96% - 115%, and the soundness coefficient was 0. 9986. By these two methods using magnetic microparticle can be shortened. The accuracy and precision are well enough for clinical and environmental analysis. Compared these two methods, magnetic microparticle using as the first-antibody was more simple and faster.