Dirks Niek F, Martens Frans, Vanderschueren Dirk, Billen Jaak, Pauwels Steven, Ackermans Mariëtte T, Endert Erik, Heijer Martin den, Blankenstein Marinus A, Heijboer Annemieke C
Department of Clinical Chemistry, Endocrine Laboratory, VU University Medical Center, Amsterdam, The Netherlands.
Department of Clinical and Experimental Medicine KU Leuven, Laboratory of Clinical and Experimental Endocrinology, Leuven, Belgium; Clinical Department of Laboratory Medicine, University Hospitals Leuven, Leuven, Belgium.
J Steroid Biochem Mol Biol. 2016 Nov;164:127-133. doi: 10.1016/j.jsbmb.2015.12.003. Epub 2015 Dec 10.
To assess a patient's vitamin D status the precursor metabolite 25-hydroxyvitamin D can be determined. However, measurement of 1,25-dihydroxyvitamin D is required when disorders of 1a-hydroxylation, extrarenal 1a-hydroxylation, or vitamin D receptor defects are suspected.
The aim of this study was to determine reference values for 1,25-dihydroxyvitamin D and D using a 2D ID-UPLC-MS/MS method.
The LC-MS/MS method, able to measure picomolar concentrations of both 1,25-dihydroxyvitamin D and D in human serum, was extensively validated. Intra-assay variations were <5% and 8.5% and <7.5% and 11%, for 1,25-dihydroxyvitamin D and D, respectively, over the whole dynamic range (3.1-376 and 3.1-652pmol/L). Limit of quantitation was 3.4pmol/L for both compounds. Our method correlated well with a published LC-MS/MS method (r=0.87) and with the average 1,25-dihydroxyvitamin D results of the vitamin D External Quality Assessment Scheme (DEQAS) determined with LC-MS/MS (r=0.93). Reference ranges, determined in 96 plasma samples of healthy volunteers were 59-159pmol/L and <17pmol/L for respectively 1,25-dihydroxyvitamin D and D. The female part of the reference group showed a statistically significant decrease of 1,25-dihydroxyvitamin D concentrations with age. The presence of significantly higher average 1,25-dihydroxyvitamin D levels in premenopausal women taking oral contraceptive pills compared to postmenopausal women suggests that this effect is estrogen-related, as estrogens lead to a higher vitamin D binding protein.
The major finding of the present study is a reference interval of 59-159pmol/L for 1,25-dihydroxyvitamin D determined with a highly sensitive and precise LC-MS/MS method.
为评估患者的维生素D状态，可测定前体代谢物25-羟基维生素D。然而，当怀疑存在1α-羟化、肾外1α-羟化或维生素D受体缺陷紊乱时，则需要测定1,25-二羟基维生素D。
本研究的目的是使用二维亲水作用色谱-串联质谱（2D ID-UPLC-MS/MS）方法确定1,25-二羟基维生素D和D的参考值。
液相色谱-串联质谱（LC-MS/MS）方法能够测定人血清中皮摩尔浓度的1,25-二羟基维生素D和D，并得到了广泛验证。在整个动态范围内（3.1 - 376和3.1 - 652 pmol/L），1,25-二羟基维生素D和D的批内变异分别<5%和8.5%，以及<7.5%和11%。两种化合物的定量限均为3.4 pmol/L。我们的方法与已发表的LC-MS/MS方法相关性良好（r = 0.87），并且与用LC-MS/MS测定的维生素D外部质量评估计划（DEQAS）的平均1,25-二羟基维生素D结果相关性良好（r = 0.93）。在96份健康志愿者的血浆样本中确定的参考范围，1,25-二羟基维生素D和D分别为59 - 159 pmol/L和<17 pmol/L。参考组中的女性部分显示，1,25-二羟基维生素D浓度随年龄有统计学意义的下降。与绝经后女性相比，服用口服避孕药的绝经前女性平均1,25-二羟基维生素D水平显著更高，这表明这种影响与雌激素有关，因为雌激素会导致更高的维生素D结合蛋白。
本研究的主要发现是，用高灵敏度和精密度的LC-MS/MS方法测定的1,25-二羟基维生素D的参考区间为59 - 159 pmol/L。
