This paper reports the establishment of solid-phase two-antibody sandwich immunoradiometric assay （IRMA） for human thyroid stimulating hormone （hTSH）

using the biotin-avidin system （BAS） separation technique. The intraassay CV of the assay is 1.4%—8.3%

the interaassay CV is 6.1%—8.4%

the sensitivity is 0.04mIU/L in serum and the average recovery rate 100.16%. The solid-phase tubes BAS-IRMA has being used to measure 20 serum samples and the results are compared with IRMA. There was a good linear correlation between the results of this method and that of the common IRMA method by statistical analysis. The sensitivity of the former is a little bit better than the common IRMA established under the same condition.