Wise Stephen A, Tai Susan S-C, Nelson Michael A, Burdette Carolyn Q, Camara Johanna E, Hoofnagle Andrew N, Laha Thomas J, Carter Graham D, Jones Julia, Williams Emma L, Barclay Zoe J, Jones Glenville, Kaufmann Martin, Binkley Neil, Kapoor Amita, Ziegler Toni, Cashman Kevin D, Dowling Kirsten G, Sempos Christopher T
National Institute of Standards and Technology, Chemical Sciences Division, Gaithersburg, MD 20899.
University of Washington, Department of Laboratory Medicine, Seattle, WA 98195-7110.
J AOAC Int. 2017 Sep 1;100(5):1308-1317. doi: 10.5740/jaoacint.17-0183. Epub 2017 Jul 24.
Six laboratories associated with the Vitamin D Standardization Program (VDSP) participated in an interlaboratory comparison of LC with tandem MS (MS/MS) methods for the determination of 24,25-dihydroxyvitamin D3 [24,25(OH)2D3] in human serum. The laboratories analyzed two different serum-based Standard Reference Materials (SRMs) intended for use in the determination of 25-hydroxyvitamin D and 30 samples from the Vitamin D External Quality Assessment Scheme (DEQAS). All laboratory methods for 24,25(OH)2D3 were based on isotope dilution LC-MS/MS; three of the methods used derivatization of the vitamin D metabolites before LC-MS/MS. Laboratory results were compared to the National Institute of Standards and Technology (NIST) results, which were obtained using their newly developed candidate reference measurement procedure for 24,25(OH)2D3. Laboratory results for the SRM samples varied in comparability to the NIST results, with one laboratory in excellent agreement (-1.6% mean bias), three laboratories at 10-15% mean bias, and the remaining laboratory at 36% mean bias. For the 30 DEQAS samples, the mean bias for the five laboratories ranged from 6 to 15%; however, the SD of the bias ranged from 8 to 29%. As a result of this intercomparison study, one laboratory discovered and corrected a method calculation error and another laboratory modified and improved their LC-MS/MS method.
与维生素D标准化计划（VDSP）相关的六个实验室参与了一项实验室间比对，该比对采用液相色谱-串联质谱（LC-MS/MS）方法测定人血清中的24,25-二羟基维生素D3 [24,25(OH)2D3]。这些实验室分析了两种不同的基于血清的标准参考物质（SRM），它们旨在用于测定25-羟基维生素D，还分析了来自维生素D外部质量评估计划（DEQAS）的30个样本。所有测定24,25(OH)2D3的实验室方法均基于同位素稀释LC-MS/MS；其中三种方法在LC-MS/MS之前对维生素D代谢物进行衍生化处理。实验室结果与美国国家标准与技术研究院（NIST）的结果进行了比较，NIST的结果是使用其新开发的24,25(OH)2D3候选参考测量程序获得的。SRM样本的实验室结果与NIST结果的可比性各不相同，一个实验室的结果一致性极佳（平均偏差为-1.6%），三个实验室的平均偏差为10%-15%，其余一个实验室的平均偏差为36%。对于30个DEQAS样本，五个实验室的平均偏差在6%至15%之间；然而，偏差的标准差在8%至29%之间。作为此次比对研究的结果，一个实验室发现并纠正了方法计算错误，另一个实验室对其LC-MS/MS方法进行了修改和改进。
