How Much “UFC” Is Really Cortisol?

摘要: When urinary free cortisol (UFC) determinations became readily available for clinical use in 1968 (1), chromatographic methods were cumbersome. The first competitive protein-binding method (radiotransinassay) (1) used human corticosteroid-binding globulin (transcortin) as the binding protein. specificity of assay was enhanced by Fuller’s earth agent to adsorb unbound fraction because it takes up some competing steroids differentially (2). reference interval ∼10–100 μg/day (30–300 nmol/day). When radioimmunoassays, based on same principle but using antibodies raised linked albumin, popular during 1970s, assumed that these would be more specific cortisol, this assumption not warranted. As pointed out recently (3), most articles published over past 20 years have quoted even higher values, reflecting a significant lack specificity. In 1976, Chattoraj et al. (4) found values UFC after combined thin-layer and column chromatography approximately one-half those original did Schoneshofer …