Measurement of specific activity of radiolabelled antigens by a simple radioimmunoassay technique

A simple radioimmunoassay (RIA) technique for measurement of specific activity of radiolabelled antigen is described. The technique involves setting up of a conventional RIA using multiple amounts of radiolabelled antigen as the unknown substance together with several RIA tubes containing the same amount of radiolabelled antigen with various known amounts of stable carrier. The known and unknown substances are equated at identical B/F ratio which would give the amounts of radiolabelled antigen. Counting the radioactivity in a counter with known efficiency gives its radioactive strength. (author)