Castoldi Simone, Cozzi Valeria, Baldelli Sara, Fucile Serena, Clementi Emilio, Cattaneo Dario
Unit of Clinical Pharmacology, ASST Fatebenefratelli Sacco University Hospital.
Clinical Pharmacology Unit, Department of Biomedical and Clinical Sciences, CNR Institute of Neuroscience, L. Sacco University Hospital, Università di Milano, Milan.
Ther Drug Monit. 2018 Feb;40(1):140-143. doi: 10.1097/FTD.0000000000000473.
An enzymatic immunoassay is under development by ARK Diagnostics, Inc for the quantification of plasma concentrations of linezolid (LZD). In this study, the authors aimed to assess the performance of this immunoassay using a validated high-performance liquid chromatography (HPLC) ultraviolet method as reference.
Within- and between-day in vitro inaccuracy and imprecision of the ARK LZD assay were firstly tested using spiked quality controls (QC) provided by the kit manufacturer. Subsequently, the performance of the immunoassay was verified in vivo by analyzing 170 trough LZD plasma samples from patients on antibiotic therapy.
Imprecision of the spiked QCs resulted in every instance less than 7.0% and the inaccuracy ranged from -1.5% to 6.6%. The linear correlation between the 2 methods was documented by the Pearson analysis of plasma samples from patients on LZD therapy (coefficient = 0.9619). By Bland-Altman comparison, 8.2% of the patient samples resulted out of the limits ranging from -27.0% to +33.5%, with most of them having LZD concentrations exceeding 10 mg/L.
Acceptable analytical performance of the ARK LZD immunoassay has been demonstrated both with spiked QC and patients' samples, making it a viable alternative to HPLC for the therapeutic drug monitoring of LZD in clinical practice in laboratory hospitals that do not have HPLC equipment.
ARK诊断公司正在开发一种酶免疫测定法，用于定量测定利奈唑胺（LZD）的血浆浓度。在本研究中，作者旨在以经过验证的高效液相色谱（HPLC）紫外法作为参考，评估这种免疫测定法的性能。
首先使用试剂盒制造商提供的加标质量控制品（QC）测试ARK LZD测定法的日内和日间体外不准确性和不精密度。随后，通过分析170例接受抗生素治疗患者的LZD血浆谷浓度样本，在体内验证免疫测定法的性能。
加标QC的不精密度在每种情况下均小于7.0%，不准确性范围为-1.5%至6.6%。通过对接受LZD治疗患者的血浆样本进行Pearson分析，记录了两种方法之间的线性相关性（系数=0.9619）。通过Bland-Altman比较，8.2%的患者样本超出了-27.0%至+33.5%的范围，其中大多数患者的LZD浓度超过10mg/L。
在加标QC和患者样本中均证明了ARK LZD免疫测定法具有可接受的分析性能，这使其成为没有HPLC设备的实验室医院临床实践中LZD治疗药物监测的一种可行替代方法，可替代HPLC。
