Schöneshöfer M, Kage A, Weber B, Lenz I, Köttgen E
Clin Chem. 1985 Apr;31(4):564-8.
This is a fully automated method for the specific assessment of urinary free cortisol. A 1-mL urine sample is concentrated and prepurified on a reversed-phase precolumn with alkaline, acid, and organic washes. After selective elution, the cortisol-containing organic eluate is "polarized" by admixing water in such a way that cortisol is focused on the top of a second reversed-phase precolumn. From this precolumn, cortisol is desorbed by backflush, separated from the still-remaining related compounds on an analytical column, and finally detected by ultraviolet absorbance. Losses of cortisol throughout the total procedure are negligible and thus external calibration is feasible for quantification. CVs were 4.1% for interassay variability, 2.6% for intra-assay variability. Cortisol concentrations down to 15 nmol/L are assayable, we estimated the median amount of free cortisol excreted daily by normal students, outpatients, hospitalized patients, and patients under intensive care. After stimulation with corticotropin1-24, the median concentration of free cortisol in urine increased from 99 nmol/L to 1238 nmol/L (n = 6). Results by radioimmunoassay for normal persons and hospitalized patients were about fourfold those by this technique. The same method can also be used for free cortisone in urine.
这是一种用于特异性评估尿游离皮质醇的全自动方法。取1 mL尿样，通过碱性、酸性和有机洗涤在反相预柱上进行浓缩和预纯化。选择性洗脱后，通过混合水使含皮质醇的有机洗脱液“极化”，使皮质醇聚焦在第二个反相预柱顶部。皮质醇从该预柱通过反冲解吸，在分析柱上与仍残留的相关化合物分离，最后通过紫外吸收进行检测。整个过程中皮质醇的损失可忽略不计，因此外部校准可用于定量。批间变异系数为4.1%，批内变异系数为2.6%。可检测低至15 nmol/L的皮质醇浓度，我们估计了正常学生、门诊患者、住院患者和重症监护患者每日排泄的游离皮质醇中位数。用促肾上腺皮质激素1-24刺激后，尿中游离皮质醇的中位数浓度从99 nmol/L增加到1238 nmol/L（n = 6）。正常人及住院患者的放射免疫分析结果约为此技术结果的四倍。相同方法也可用于尿中游离可的松的检测。
