Andrea Prader Award. Clinical Steroidology. Coming of age.

The determination of steroid concentrations in urine and plasma is an indispensable part of the diagnostic work-up in endocrinology. Since the description of the color reaction for determination of 17-ketosteroids by Zimmermann in 1935, a vast amount of work has been invested in the specialty of clinical chemistry, which we called 'clinical steroidology'. Until the early fifties, color reactions for block determinations of C19 and C21 steroids in urine and plasma were the strongholds of steroid clinical chemistry. Around 1952, paper chromatography, and later on column chromatography were added, which afforded fractionation and individual determinations of steroids in body fluids. The final achievement and almost absolute quantification of almost 50 steroid metabolites ('profile') in urine was achieved by capillary glass column chromatography-mass spectrometry (GC-MS), which came into clinical usage around the mid-eighties. For estimation of plasma steroids radioimmunoassays (RIA) were introduced during the sixties. A whole body of physiology and pathology was erected on the basis of steroid RIAs. Recent investigation, however, revealed that steroid RIAs yield unreliable results at low concentrations due to cross reactions and interferences by impurities of samples. The newly (nineties) developed method of isotope dilution/GC-MS produced highly accurate values of small amounts of steroids and became the gold standard of plasma steroid determinations. Thus 'clinical steroidology' has certainly come of age.