Dias V C, Legatt D F, Yatscoff R W
Department of Laboratory Medicine and Pathology, University of Alberta Hospitals, Edmonton, Canada.
Clin Biochem. 1997 Mar;30(2):155-62. doi: 10.1016/s0009-9120(96)00162-2.
The purpose of this work was to develop applications for the EMIT Cyclosporine (CsA) Assay on the Hitachi 911 and 917 analyzers.
Instrument settings were optimized to arrive at the following assay characteristics on the Hitachi 917. Limit of sensitivity was 50 micrograms/L. Intra-assay coefficients of variation (CV) were 8.1% (n = 20; mean = 62 micrograms/L) and 4.2% (n = 20; mean = 315 micrograms/L), while interassay CVs were 13.0% (n = mean = 73 micrograms/L) and 5.7% (n = 43; mean = 391 micrograms/L). Recoveries of 95-104% were obtained by spiking aliquots of 3 whole blood patient pools of known CsA concentrations with CsA. Serial dilutions of 3 patient specimens demonstrated linear relationships between expected and actual CsA concentrations (r = 0.99, 0.99, 0.98; regression lines: y = 1.19x -17.1; y = 0.75x + 18.0; y = 1.01x + 3.7). Specimen carryover was not evident. Calibration stability is at least 10 days. Comparable assay characteristics were found for the Hitachi 911. Sequentially-collected trough whole blood specimens from renal (n = 3), liver (n = 3) and heart (n = 4) transplant patients prescribed CsA were collected up to 78 days post-transplant and analyzed by EMIT on the Hitachi 917 and also by fluorescence polarization immunoassay (FPIA) and high performance liquid chromatography (HPLC). The following linear regression equations were produced for the renal [EMIT = 0.801 (TDx) + 4.98, r = 0.91, Sy/x = 32, n = 37; EMIT = 0.877 (HPLC) + 56, r = 0.87, Sy/x = 38, n = 37]; liver [EMIT = 0.808 (TDx) - 27, r = 0.94, Sy/x = 42, n = 37; EMIT = 0.953 (HPLC) + 44, r = 0.89, Sy/x = 57, n = 37] and heart [EMIT = 0.820 (TDx) - 24, r = 0.94, Sy/x = 31, n = 45, EMIT = 0.956 (HPLC) + 54, r = 0.91, Sy/x = 38, n = 45] patient samples. FPIA values average 32% more than EMIT-derived CsA concentrations on the Hitachi 917, which in turn averaged 15% more than HPLC values. In addition, these levels were compared intra-individually. CsA concentrations within all patients were significantly higher (p < 0.05, paired t-test) by FPIA compared to EMIT and by FPIA compared to HPLC. Although CsA concentrations within most patients were significantly higher (p < 0.05) by EMIT compared to HPLC, levels determined in 4 transplant patients (1 renal, 1 liver, 2 heart) were not different.
Development of applications for the EMIT CsA Assay on two highly automated, random access instruments, the Hitachi 911 and Hitachi 917, enhances the versatility of the immunoassay for routine therapeutic drug monitoring of this immunosuppressant in the clinical setting.
本研究旨在开发适用于日立911和917分析仪的EMIT环孢素（CsA）检测方法。
对仪器设置进行了优化，以获得日立917分析仪的以下检测特性。灵敏度限值为50微克/升。批内变异系数（CV）分别为8.1%（n = 20；均值 = 62微克/升）和4.2%（n = 20；均值 = 315微克/升），而批间CV分别为13.0%（n =均值 = 73微克/升）和5.7%（n = 43；均值 = 391微克/升）。通过向3个已知CsA浓度的全血患者样本库等分试样中加入CsA，回收率为95 - 104%。3个患者标本的系列稀释显示预期和实际CsA浓度之间呈线性关系（r = 0.99、0.99、0.98；回归线：y = 1.19x - 17.1；y = 0.75x + 18.0；y = 1.01x + 3.7）。标本携带污染不明显。校准稳定性至少为10天。在日立911分析仪上发现了类似的检测特性。收集了肾移植（n = 3）、肝移植（n = 3）和心脏移植（n = 4）患者在移植后长达78天的序贯采集的谷值全血标本，并在日立917分析仪上通过EMIT法进行分析，同时也通过荧光偏振免疫分析法（FPIA）和高效液相色谱法（HPLC）进行分析。对肾移植患者样本得出以下线性回归方程[EMIT = 0.801（TDx）+ 4.98，r = 0.91，Sy/x = 32，n = 37；EMIT = 0.877（HPLC）+ 56，r = 0.87，Sy/x = 38，n = 37]；肝移植患者样本[EMIT = 0.808（TDx） - 27，r = 0.94，Sy/x = 42，n = 37；EMIT = 0.953（HPLC）+ 44，r = 0.89，Sy/x = 57，n = 37]；心脏移植患者样本[EMIT = 0.820（TDx） - 24，r = 0.94，Sy/x = 31，n = 45，EMIT = 0.956（HPLC）+ 54，r = 0.91，Sy/x = 38，n = 45]。在日立917分析仪上，FPIA值平均比EMIT法测得的CsA浓度高32%，而EMIT法测得的浓度又平均比HPLC值高15%。此外，还对个体内的这些水平进行了比较。与EMIT法相比，FPIA法测得的所有患者体内CsA浓度均显著更高（p < 0.05，配对t检验），与HPLC法相比也是如此。尽管与HPLC法相比，大多数患者体内EMIT法测得的CsA浓度显著更高（p < 0.05），但4例移植患者（1例肾移植、1例肝移植、2例心脏移植）体内测得的水平并无差异。
在两台高度自动化的随机存取仪器——日立911和日立917上开发EMIT CsA检测方法的应用，增强了该免疫分析法在临床环境中对这种免疫抑制剂进行常规治疗药物监测的通用性。
