Rapid, specific assay for plasma cortisol by competitive protein binding.
We describe a modified competitive protein-binding method for assay of plasma cortisol. Plasma samples are deproteinized by dilution with an ethanol/phosphate buffer, followed by heating at 100 degrees C for 2 min. Horse serum is used as the source of transcortin. Free radioactivity is separated from the protein-bound component by partition into liquid scintillation counting within 60 min. The assay has better specificity and precision than a competitive protein-binding assay in which ethanol extraction and Florisil adsorbent are used, and results correlate well with those of a specific radioimmunoassay method.
D001667:Binding, Competitive; D003429:Cross Reactions; D006801:Humans; D006854:Hydrocortisone / Q000097:blood*; D011863:Radioimmunoassay; D011869:Radioligand Assay / Q000379:methods; D014156:Transcortin
D014156:Transcortin; D006854:Hydrocortisone