Institute of Clinical Chemistry and Clinical Pharmacology, University Hospital, Bonn, Germany.
Department of Laboratory Medicine, Division of Clinical Chemistry, Karolinska University Hospital, Karolinska Institutet, Huddinge, Sweden.
J Steroid Biochem Mol Biol. 2019 Jun;190:115-125. doi: 10.1016/j.jsbmb.2019.03.025. Epub 2019 Mar 30.
Serum concentrations of lathosterol, the plant sterols campesterol and sitosterol and the cholesterol metabolite 5α-cholestanol are widely used as surrogate markers of cholesterol synthesis and absorption, respectively. Increasing numbers of laboratories utilize a broad spectrum of well-established and recently developed methods for the determination of cholesterol and non-cholesterol sterols (NCS). In order to evaluate the quality of these measurements and to identify possible sources of analytical errors our group initiated the first international survey for cholesterol and NCS. The cholesterol and NCS survey was structured as a two-part survey which took place in the years 2013 and 2014. The first survey part was designed as descriptive, providing information about the variation of reported results from different laboratories. A set of two lyophilized pooled sera (A and B) was sent to twenty laboratories specialized in chromatographic lipid analysis. The different sterols were quantified either by gas chromatography-flame ionization detection, gas chromatography- or liquid chromatography-mass selective detection. The participants were requested to determine cholesterol and NCS concentrations in the provided samples as part of their normal laboratory routine. The second part was designed as interventional survey. Twenty-two laboratories agreed to participate and received again two different lyophilized pooled sera (C and D). In contrast to the first international survey, each participant received standard stock solutions with defined concentrations of cholesterol and NCS. The participants were requested to use diluted calibration solutions from the provided standard stock solutions for quantification of cholesterol and NCS. In both surveys, each laboratory used its own internal standard (5α-cholestane, epicoprostanol or deuterium labelled sterols). Main outcome of the survey was, that unacceptably high interlaboratory variations for cholesterol and NCS concentrations are reported, even when the individual laboratories used the same calibration material. We discuss different sources of errors and recommend all laboratories analysing cholesterol and NCS to participate in regular quality control programs.
麦角甾醇、植物固醇菜油固醇和谷固醇以及胆固醇代谢产物 5α-胆甾烷醇的血清浓度被广泛用作胆固醇合成和吸收的替代标志物。越来越多的实验室利用广泛的、经过良好验证的和最近开发的方法来测定胆固醇和非胆固醇甾醇（NCS）。为了评估这些测量的质量并确定可能的分析误差来源，我们小组启动了第一个胆固醇和 NCS 的国际调查。胆固醇和 NCS 调查分为两部分，分别在 2013 年和 2014 年进行。第一部分调查是描述性的，提供了来自不同实验室报告结果的差异信息。一组两种冻干的混合血清（A 和 B）被送到 20 家专门从事色谱脂质分析的实验室。不同的甾醇通过气相色谱-火焰离子化检测、气相色谱或液相色谱-质谱选择性检测进行定量。要求参与者在提供的样品中按照他们的常规实验室常规测定胆固醇和 NCS 浓度。第二部分设计为干预性调查。22 家实验室同意参与，并再次收到两种不同的冻干混合血清（C 和 D）。与第一次国际调查不同，每个参与者都收到了具有定义浓度的胆固醇和 NCS 的标准储备溶液。要求参与者使用提供的标准储备溶液中的稀释校准溶液来定量胆固醇和 NCS。在两次调查中，每个实验室都使用自己的内标（5α-胆甾烷、依考前列醇或氘标记甾醇）。调查的主要结果是，即使个别实验室使用相同的校准材料，也报告了胆固醇和 NCS 浓度的不可接受的高实验室间差异。我们讨论了不同的误差来源，并建议所有分析胆固醇和 NCS 的实验室参加定期的质量控制计划。
