Abstract: PREPARATION OF FERRITIN NATIONAL STANDARDShen Hongzheng Jiao Yan Xu Ligen(China National Institute of Control for Pharmaceutical and Biological Products, Beijing 100050) ABSTRACTThe raw material of ferritin is analyzed for preparation of ferritin national standard (NS) for immunoassay. No impure zone is found by polyacrylamide gel electrophoresis. The protein amount is 1.06 g/L and the immunoactivity is 1.015 g/L by RIA, with its doseresponse curve being parallel to that of Human Ferritin 2nd International Standard coded 80/578(IS). This shows that the material used is suitable for preparation of ferritin NS. 1.25 mg of raw material diluted in 0.01 mol/L phosphate buffer solution (pH7.4) containing 1% human serum albumin is distributed into aliquot of 0.8 mL(2 μg per ampoule),lyophilized and assayed by RIA. The mean value of this NS is 1.962 μg per ampoule in terms of IS. Similar values are obtained for the ferritin contents of quality control serum samples at different content levels when either IS or NS is used as the assay calibrator. This indicates that there is no statistically significant diference between the serum sample values at the same levels.Key words ferritin international standard national standard radioimmunoassay calibration