VALIDATION OF A SPECIFIC RADIOIMMUNOASSAY TO MEASURE PLASMA CORTISOL IN THE FETAL SHEEP

A procedure utilizing co-chromatography and complementary antiserum comparisons was employed to assess the specificity of a cortisol radioimmunoassay for use in the chronically catheterized fetal sheep preparation. Complementary antiserum comparisons is a technique by which two different cortisol antisera, prepared from conjugates attached at opposite ends of the cortisol molecule, were used to determine cortisol concentrations in the same ovine fetal plasma specimens. Results were not significantly different between the two groups, each measured by a different antiserum. This procedure may be used to assess assay specificity in any species in which steroid radioimmunoassays are being adapted. © 1979.