Department of Pharmacy, University of Miyazaki Hospital, Miyazaki, Japan.
Division of Pediatrics, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan.
J Clin Lab Anal. 2021 Mar;35(3):e23661. doi: 10.1002/jcla.23661. Epub 2020 Nov 22.
The concentration of MTX in blood is often measured quickly and easily by immunoassays. Thus, immunoassays may facilitate the easy determination of the concentration of MTX in the cerebrospinal fluid (CSF). In this study, we measured methotrexate (MTX) concentrations in the CSF using a high-performance liquid chromatography (HPLC) method intended for analyzing CSF matrices and a chemiluminescence immunoassay (CLIA) method intended for assessing serum and plasma matrices and verified the differences in the results of the two methods.
HPLC analysis for MTX in the CSF was performed using a Prominence UFLC system with a C18 column. The HPLC method was validated in accordance with the 2018 FDA guideline. The CLIA method was performed using an ARCHITECT i1000SR system intended for serum and plasma matrices. A total of 47 CSF samples (14 clinical and 33 spiked specimens) were analyzed using the two methods.
The HPLC method passed the validation criteria. The concentration of MTX in the same sample, determined using the HPLC and CLIA methods, differed proportionally; the percent difference in the concentrations averaged -23.0% (95% confidence interval: -36.9% to -9.1%) as revealed by the Bland-Altman plot. The relationship between the measured values, evaluated using the Passing-Bablok regression, was as follows: HPLC = 1.205 × CLIA - 0.024.
The equation deduced in this study can be used to correct the concentration of MTX measured using the CLIA method.
通常可以通过免疫测定法快速、轻松地测量血液中的 MTX 浓度。因此，免疫测定法可能有助于轻松确定脑脊液（CSF）中 MTX 的浓度。在这项研究中，我们使用旨在分析 CSF 基质的高效液相色谱（HPLC）方法和旨在评估血清和血浆基质的化学发光免疫测定（CLIA）方法来测量 CSF 中的甲氨蝶呤（MTX）浓度，并验证了两种方法的结果之间的差异。
使用 Prominence UFLC 系统和 C18 柱对 CSF 中的 MTX 进行 HPLC 分析。HPLC 方法按照 2018 年 FDA 指南进行验证。CLIA 方法使用 ARCHITECT i1000SR 系统进行，该系统用于血清和血浆基质。使用两种方法分析了 47 个 CSF 样本（14 个临床样本和 33 个加标样本）。
HPLC 方法通过了验证标准。使用 HPLC 和 CLIA 方法测定同一样本中的 MTX 浓度呈比例差异；Bland-Altman 图显示，浓度的平均差异为 -23.0%（95%置信区间：-36.9%至-9.1%）。通过 Passing-Bablok 回归评估的测定值之间的关系如下：HPLC = 1.205 × CLIA - 0.024。
本研究推导出的方程可用于校正 CLIA 方法测量的 MTX 浓度。
