USE OF SODIUM-SALICYLATE AS A BLOCKING-AGENT FOR CORTISOL-BINDING-GLOBULIN IN A RADIOIMMUNOASSAY FOR CORTISOL ON UNEXTRACTED PLASMA

Cortisol antiserum was raised against a cortisol 3-O-(carboxymethyl) oxime-bovine serum albumin conjugate. A 125I-labelled cortisol-tyrosine methyl ester conjugate was also prepared for use in the assay. The radioimmunoassay developed involved no pre-treatment or extraction of the samples before analysis and was extremely simple to perform. Comparison with another radioimmunoassay for cortisol and with the Mattingly fluorimetric assay gave good correlation.