A Rapid, Simple Solid Phase RIA System for Detection of AFP in Human Serum

Development. optimization and validation of radio immunoassay (RIA) using solid phase-magnetic particles for the measurement of alpha-fetoprotein (AFP) in human serum are described. The production of polyclonal antibodies was undertaken by immunizing four white New Zealand rabbits subcutaneously. The preparation of 125IAFP was carried out using iodogen oxidation method. The purification of the polyclonal antibody was performed using caprylic acid precipitation method. Thc activation of the low density magnetizable cellulose iron oxide particles using I, I-carbonyl diimidazole (CDI) and coupling of these solid phase particles with the purified anti-AFP antiserum were carried out. The preparation of AFP standards was undertaken by diluting cord sera with assay buffer. Optimization and validation of the assay were carried out. The reproducibility as measured by the intra- and inter-assay variations is satisfactory. The recovery and dilution tests indicated accurate calibration and appropriate matrix. Thc present technique agreed well with the currently used commercial kit (DPC-IRMA). The magnetic particles of the present system for estimation of AFP retain their characteristics during storage for 6 months at 4 degree. In conclusion, this technique proved to be sensitive, specific, precise and accurate for routine laboratory use