[The progress and methodologic problems of in vitro radioassay]

The history of development of in vitro radioassays is reviewed. The basic principles and clinical uses of saturation analysis, competitive radioassay and immunoradiometric assay are described. The more rapid, sensitive, specific and accurate assays are required at all times. However, it is well known that autoantibodies or heterophilic antibodies in serum interfere with radioassay and cause false results. Here I present the technical problems of the assay in the presence of such interfering substances which need to be resolved and also discussed the discrepancy between bioactivity and immunoreactivity in the assay.