A rapid method for the purification and radioimmunoassay of human alpha-fetoprotein

Human alpha-fetoprotein (AFP) was isolated from cord serum on an immunoadsorbent column obtained by covalently linking rabbit anti AFP to cyanogen bromide activated Sepharose. Bound AFP was eluted with 8 M urea with better than 50% recovery. The purified AFP was iodinated prior to its use in a double antibody radioimmunoassay. The purification and radioimmunoassay employ commercially available materials. A standard inhibition curve was obtained which allowed determination of AFP levels between 50 and 100 ng/ml in human serum. The assay was verified by measureing AFP levels in normal female serum, pregnancy serum, cord serum, hepatoma ascitic fluid and a standardized AFP solution.