Improved assay for urinary 17-hydroxycorticosteroids.

We describe a simple, rapid, reliable method for determining urinary 17-hydroxycorticosteroids. A neutral resin (Amberlite XAD-2), which is a non-ionic cross-linked polystyrene, is used to extract and concentrate the steroids, which are then quantitatively determined with the Porter-Silber reaction. Use of the resin eliminates the need for enzymatic hydrolysis and n-butanol extractions, thereby decreasing analysis time considerably; results can be obtained within 3 h of receipt of specimens. Most of the nonsteroidal Porter-Silber chromogens are removed, resulting in a method that is highly specific and sensitive, even at low concentrations (0.6 mg/liter), and so more accurate and reproducible than currently used methods.