Tripodi A, Chantarangkul V, Clerici M, Negri B, Mannucci P M
Angelo Bianchi Bonomi Hemophilia and Thrombosis Center, IRCCS Maggiore Hospital and University of Milano, Italy.
Thromb Haemost. 1997 Aug;78(2):855-8.
A key issue for the reliable use of new devices for the laboratory control of oral anticoagulant therapy with the INR is their conformity to the calibration model. In the past, their adequacy has mostly been assessed empirically without reference to the calibration model and the use of International Reference Preparations (IRP) for thromboplastin. In this study we reviewed the requirements to be fulfilled and applied them to the calibration of a new near-patient testing device (TAS, Cardiovascular Diagnostics) which uses thromboplastin-containing test cards for determination of the INR. On each of 10 working days citrated whole blood and plasma samples were obtained from 2 healthy subjects and 6 patients on oral anticoagulants. PT testing on whole blood and plasma was done with the TAS and parallel testing for plasma by the manual technique with the IRP CRM 149S. Conformity to the calibration model was judged satisfactory if the following requirements were met: (i) there was a linear relationship between paired log-PTs (TAS vs CRM 149S); (ii) the regression line drawn through patients data points, passed through those of normals; (iii) the precision of the calibration expressed as the CV of the slope was <3%. A good linear relationship was observed for calibration plots for plasma and whole blood (r = 0.98). Regression lines drawn through patients data points, passed through those of normals. The CVs of the slope were in both cases 2.2% and the ISIs were 0.965 and 1.000 for whole blood and plasma. In conclusion, our study shows that near-patient testing devices can be considered reliable tools to measure INR in patients on oral anticoagulants and provides guidelines for their evaluation.
使用国际标准化比值（INR）对口服抗凝治疗进行实验室控制的新型设备能否可靠使用的一个关键问题是其是否符合校准模型。过去，大多通过经验评估其适用性，而未参考校准模型以及用于凝血活酶的国际参考制剂（IRP）。在本研究中，我们回顾了需要满足的要求，并将其应用于一种新型即时检测设备（TAS，心血管诊断公司）的校准，该设备使用含凝血活酶的测试卡来测定INR。在10个工作日中的每一天，从2名健康受试者和6名接受口服抗凝剂治疗的患者中采集枸橼酸盐全血和血浆样本。使用TAS对全血和血浆进行凝血酶原时间（PT）检测，并通过手动技术使用IRP CRM 149S对血浆进行平行检测。如果满足以下要求，则判定符合校准模型：（i）配对的对数PT（TAS与CRM 149S）之间存在线性关系；（ii）通过患者数据点绘制的回归线经过正常数据点；（iii）以斜率的变异系数（CV）表示的校准精密度<3%。血浆和全血的校准图呈现出良好的线性关系（r = 0.98）。通过患者数据点绘制的回归线经过正常数据点。全血和血浆的斜率CV均为2.2%，国际敏感度指数（ISI）分别为0.965和1.000。总之，我们的研究表明，即时检测设备可被视为测量接受口服抗凝剂治疗患者INR的可靠工具，并为其评估提供了指导原则。
