用于测定尿游离皮质醇浓度的免疫分析试剂盒的特异性评估。

Specificity assessment of immunoassay kits for determination of urinary free cortisol concentrations.

作者信息

Horie Hitoshi, Kidowaki Takeshi, Koyama Yuhei, Endo Tatsuji, Homma Keiko, Kambegawa Akira, Aoki Norihiko

机构信息

Mitsubishi Kagaku Bio-Clinical Laboratories, INC., 3-30-1 Shimura, Itabashi-ku, and Department of Clinical Laboratories, Keio University Hospital, Tokyo, Japan.

出版信息

Clin Chim Acta. 2007 Mar;378(1-2):66-70. doi: 10.1016/j.cca.2006.10.018. Epub 2006 Nov 1.

DOI:10.1016/j.cca.2006.10.018

PMID:17174290

Abstract

BACKGROUND

In immunoassay kits for determination of urinary free cortisol (UFC) concentrations, the results vary markedly from kit to kit, so we compared in this study the reaction specificity among 4 commercially available immunoassay kits to determine the applicability of these assays in routine determination of UFC concentrations.

METHOD

Using 4 commercially available kits, cross-reaction was investigated. In addition, urine samples were fractionated by HPLC to investigate endogenous immunoreactive cortisol responses. HPLC fractions were subjected to gas chromatography-mass spectrometry (GCMS) to identify substances causing inter-kit assay discrepancies.

RESULTS

Among the 4 kits, cortisol Kit "TFB" (Immunotech; IOT-RIA method) showed the lowest cross-reaction (2.5%) for prednisolone. Furthermore, on HPLC, 87.8% of the reaction of the entire fraction was seen in the fractions corresponding to the elution position of standard cortisol with the IOT-RIA method; this was the highest percentage among the 4 kits. GCMS revealed that the substance that showed a cross-reaction with the other 3 kits was 5alpha-tetrahydrocortisol (5alpha-THF) glucuronide.

CONCLUSIONS

The IOT-RIA method was found to be the most specific for UFC. The other 3 commercially available kits showed cross-reaction with a conjugate of 5alpha-THF, found to be one of the causes of inter-kit assay discrepancies.

摘要

背景

在用于测定尿游离皮质醇（UFC）浓度的免疫分析试剂盒中，不同试剂盒的结果差异显著，因此我们在本研究中比较了4种市售免疫分析试剂盒的反应特异性，以确定这些检测方法在UFC浓度常规测定中的适用性。

方法

使用4种市售试剂盒研究交叉反应。此外，通过高效液相色谱法（HPLC）对尿样进行分离，以研究内源性免疫反应性皮质醇反应。对HPLC馏分进行气相色谱 - 质谱联用（GCMS）分析，以鉴定导致试剂盒间检测差异的物质。

结果

在这4种试剂盒中，皮质醇试剂盒“TFB”（Immunotech；IOT - RIA法）对泼尼松龙的交叉反应最低（2.5%）。此外，在HPLC分析中，采用IOT - RIA法时，整个馏分87.8%的反应出现在与标准皮质醇洗脱位置相对应的馏分中；这是4种试剂盒中比例最高的。GCMS分析显示，与其他3种试剂盒有交叉反应的物质是5α - 四氢皮质醇（5α - THF）葡糖醛酸苷。