Increasing numbers of laboratories develop new methods based on gas-liquid and high-performance liquid chromatography to determine serum concentrations of oxygenated cholesterol metabolites such as 7α-, 24(S)-, and 27-hydroxycholesterol. We initiated a first international descriptive oxycholesterol (OCS) survey in 2013 and a second interventional survey 2014 in order to compare levels of OCS reported by different laboratories and to define possible sources of analytical errors. In 2013 a set of two lyophilized serum pools (A and B) was sent to nine laboratories in different countries for OCS measurement utilizing their own standard stock solutions. In 2014 eleven laboratories were requested to determine OCS concentrations in lyophilized pooled sera (C and D) utilizing the same provided standard stock solutions of OCS. The participating laboratories submitted results obtained after capillary gas-liquid chromatography-mass selective detection with either epicoprostanol or deuterium labelled sterols as internal standards and high-performance liquid chromatography with mass selective detection and deuterated OCS as internal standard. Each participant received a clear overview of the results in form of Youden-Plots and basic statistical evaluation in its used unit. The coefficients of variation of the concentrations obtained by all laboratories using their individual methods were 58.5–73.3% (survey 1), 56.8–60.3% (survey 2); 36.2–35.8% (survey 1), 56.6–59.8, (survey 2); 61.1–197.7% (survey 1), 47.2–74.2% (survey 2) for 24(S)-, 27-, and 7α-hydroxycholesterol, respectively. We are surprised by the very great differences between the laboratories, even under conditions when the same standards were used. The values of OCS's must be evaluated in relation to the analytical technique used, the efficiency of the ample separation and the nature of the internal standard used. Quantification of the calibration solution and inappropriate internal standards could be identified as major causes for the high variance in the reported results from the different laboratories. A harmonisation of analytical standard methods is highly needed.

越来越多的实验室开发了基于气液和高效液相色谱的新方法，以确定含氧胆固醇代谢产物（如7α-，24（S）-和27-羟基胆固醇）的血清浓度。为了比较不同实验室报告的OCS水平并确定可能的分析误差来源，我们于2013年发起了第一次国际描述性羟胆固醇（OCS）调查，并于2014年发起了第二次介入性调查。2013年，一组两个冻干的血清库（A和B）被发送到不同国家的9个实验室，使用他们自己的标准储备溶液进行OCS测量。2014年，要求11个实验室使用提供的标准OCS标准储备溶液测定冻干合并血清（C和D）中的OCS浓度。参与实验室提交的结果是在毛细管气相色谱-液相色谱-质谱选择性检测中以表皮前列腺素或氘标记的固醇为内标，以及在高效液相色谱中以质量选择性检测和氘代OCS为内标所获得的结果。每个参与者都以Youden-Plots的形式清楚地了解了结果，并在其使用的单位中进行了基本的统计评估。所有实验室使用各自方法得出的浓度变化系数分别为58.5–73.3％（调查1），56.8–60.3％（调查2）；36.2–35.8％（调查1），56.6–59.8（调查2）；24（S）-，27-和7α-羟基胆固醇分别为61.1–197.7％（调查1），47.2–74.2％（调查2）。我们对实验室之间的巨大差异感到惊讶，即使在使用相同标准的条件下。必须根据所用的分析技术，充分分离的效率和所用内标的性质来评估OCS的值。校准溶液的定量分析和不适当的内部标准可被认为是不同实验室报告的结果差异很大的主要原因。高度需要分析标准方法的统一。校准溶液的定量分析和不适当的内部标准可被认为是不同实验室报告的结果差异很大的主要原因。高度需要分析标准方法的统一。校准溶液的定量分析和不适当的内部标准可被认为是不同实验室报告的结果差异很大的主要原因。高度需要分析标准方法的统一。