Abstract: PREPARATION OF TSH NATIONAL STANDARD FOR IMMUNOASSAYHuang Ying Shen Hongzheng Xu Ligen Leng Wei(National Institute for Control of Pharmaceutical and Biological Products, Beijing 100050)ABSTRACTThe first national standard of thyroid stimulating hormone (TSH) for immunoassay is prepared. The highly pure TSH from Sigma Co, are purchased and immuno activity of this material is 7 kIU/g. The batch of ampoules coded 05309412，is prepared according to the procedures used for international biological standard. The ampoule′s potency are calibrated by 8 immunoassay systems including RIA, IRMA and ELISA. The mean potency of the first national standard of TSH for immunoassay is 525 μIU per ampoule.Key words TSH national standard collaborative study