Coagulation Reference Laboratory, Department of Clinical Chemistry and Laboratory Medicine, Leiden University Medical Center, Leiden, the Netherlands.
Coagulation Reference Laboratory, Department of Clinical Chemistry and Laboratory Medicine, Leiden University Medical Center, Leiden, the Netherlands.
Thromb Res. 2021 Jun;202:1-7. doi: 10.1016/j.thromres.2021.02.018. Epub 2021 Feb 25.
Whole blood point-of-care PT/INR test devices, e.g. CoaguChek XS, are calibrated by their manufacturers. In the Netherlands, each new lot of test strips for CoaguChek XS is validated by a group of anticoagulant clinics collaborating with a Coagulation Reference Laboratory. In 2017, a new International Standard for recombinant human thromboplastin (coded rTF/16) has been established by the World Health Organization.
To assess uncertainty of the validation procedure and the magnitude of the INR bias of a series of consecutive lots of test strips imported in the Netherlands.
CoaguChek XS test strip INR results were compared to INRs determined with the new International Standard rTF/16. Comparisons were made with variable numbers of blood samples obtained from patients treated with vitamin K-antagonists. Relationships between CoaguChek XS and rTF/16 results were determined with orthogonal regression analysis. The relationships were used to assess bias and uncertainty of bias.
Average bias between CoaguChek XS test results and rTF/16 depends on the INR level. Overall, there was a trend of increasing bias and increasing uncertainty with increasing INR values. Along the sequence of 47 consecutive lots, a temporary fluctuation of bias was observed. At an INR level of 3.0 the average bias was less than 10% in all cases, but at an INR of 4.0 there were 5 lots with average bias between 10 and 15%.
Validation of test strips is useful to assess bias but depends on availability of fresh patients' samples and traceability to an accepted Reference Measurement System.
全血即时凝血酶原时间/国际标准化比值（PT/INR）检测设备，如 CoaguChek XS，由其制造商进行校准。在荷兰，每批新的 CoaguChek XS 测试条都由一组与凝血参考实验室合作的抗凝诊所进行验证。2017 年，世界卫生组织（WHO）建立了新的重组人凝血活酶国际标准（编码 rTF/16）。
评估验证程序的不确定度和一系列连续进口测试条的 INR 偏差幅度。
将 CoaguChek XS 测试条的 INR 结果与新的国际标准 rTF/16 确定的 INR 进行比较。比较是通过从接受维生素 K 拮抗剂治疗的患者中获得的可变数量的血液样本进行的。使用正交回归分析确定 CoaguChek XS 和 rTF/16 结果之间的关系。使用这些关系来评估偏差和偏差的不确定度。
CoaguChek XS 测试结果与 rTF/16 之间的平均偏差取决于 INR 水平。总体而言，随着 INR 值的增加，偏差和偏差的不确定性呈增加趋势。沿着 47 批连续批的顺序，观察到偏差的暂时波动。在 INR 水平为 3.0 的情况下，所有情况下的平均偏差都小于 10%，但在 INR 为 4.0 的情况下，有 5 批的平均偏差在 10%至 15%之间。
测试条的验证有助于评估偏差，但取决于是否有新鲜的患者样本和可追溯性至可接受的参考测量系统。
