Development of Radioimmunoassay for Alpha Fetoprotein Using Sephadex Particles as a Solid Phase System

Development, optimization and validation of radioimmunoassay (RIA) using solid phase sephadex particles for the measurement of alpha fetoprotein (AFP) in human serum or plasma are described. The preparation of ¹²⁵ I-AFP was carried out by chloramine-T oxidation method and purification of the tracer was performed using gel chromatography was carried out on sephadex G-25 column. The activation of sephadex G-25 particles using 1,1-carbonyl diimidazole (CDI) and coupling of these activated sephadex particles with polyclonal antibody of AFP produced using rabbit as a host animal were undertaken. Optimization and validation of the assay were carried out. Results showed that the assay is highly sensitive. The data of intra assay and inter assay precisions revealed consistency of the results obtained by this technique. The recovery and dilutions tests indicated accurate calibration and appropriate matrix. The present technique agreed well with the currently used commercial kit (Siemens). In conclusion, this technique proved to be sensitive, precise and accurate for routine laboratory use and in the diagnosis and management of patients with certain malignant diseases