A NEW METHOD FOR THE PRODUCTION OF A MAGNETIC IMMUNOSORBENT USED IN RADIOIMMUNOASSAY AND IMMUNORADIOMETRIC ASSAY

A method has been developed enabling the direct coupling of first or second antibody to finely dispersed magnetite (Fe3O4) The immunosorbent thus produced was applied in various radioimmunoassay systems (T3, T4, TSH, Cortisol) for the separation of bound and free antigens. The elimination of the need for ''precoating'' the magnetic particles with a polymer has several advantages. One of them lies in the ease of one-step production of the immunosorbent and other is the high antibody/magnetite ratio. The influence of the concentration of the inmmunosorbent and detergent (TWEEN 20 or TRITON X-100) on the assay parameters (Bo. NSB, etc.) has been systematically investigated and the optimum concentration of the magnetizable particles and detergent has been determined. nle reliability of magnetic separation has been validated by comparing it with the conventional PEC separation method.