Landspitali The National University Hospital of Iceland, Reykjavik, Iceland.
University of Rochester Medical Center, Rochester, NY, USA.
J Thromb Haemost. 2016 May;14(5):1043-53. doi: 10.1111/jth.13300. Epub 2016 Mar 30.
Essentials Simple and fast assaying of different anticoagulants (ACs) is useful in emergent situations. We used highly diluted prothrombin time (dPT) or highly diluted Fiix-PT (dFiix-PT) to assay ACs. Both tests could quantify target specific anticoagulants and warfarin anticoagulation. Improved results were consistently observed with the dFiix-PT compared with the dPT.
Background Assaying anticoagulants is useful in emergency situations or before surgery. Different specific assays are currently needed depending on the anticoagulant. Objectives We hypothesized that levels of warfarin, dabigatran, rivaroxaban, apixaban, and heparins could be measured with use of the diluted prothrombin time (dPT) and diluted Fiix-PT (dFiix-PT), using highly diluted thromboplastin (TP). The latter test is affected only by reduced levels of active factors II and X but corrects test plasma for other deficiencies Methods Increasing TP dilutions were used to identify suitable dilutions to measure dabigatran, rivaroxaban, apixaban, unfractionated heparin (UFH), and enoxaparin. Calibrators containing known amounts of direct oral anticoagulants (DOACs) were used to make standard curves. Citrated plasma samples were obtained from patients taking warfarin or DOACs with known drug concentrations as determined by specific assays. Results The dFiix-PT at a TP dilution of 1:1156 could be used to measure all of the drugs tested at therapeutic concentrations except for fondaparinux. The dPT achieved the same but required two TP dilutions (1:750 and 1:300). The warfarin effect could be assessed by using dFiix-PT at 1:1156 with a PT ratio identical to the international normalized ratio. Six different TPs yielded similar results, but two were less sensitive. Dabigatran, rivaroxaban, and apixaban could be accurately measured in patient samples using both dilute PT assays, but a better correlation was consistently observed between the dFiix-PT and specific assays than with the dPT. Conclusion The dFiix-PT using a single dilution of TP may be suitable to assess the anticoagulant effects of warfarin, dabigatran, rivaroxaban, apixaban, heparin, and enoxaparin.
检测不同抗凝剂（ACs）在紧急情况下或手术前非常有用。目前，不同的抗凝剂需要不同的特定检测方法。
我们使用高度稀释的凝血酶原时间（dPT）或高度稀释的 Fiix-PT（dFiix-PT）检测 ACs。这两种检测方法都可以定量检测目标特异性抗凝剂和华法林抗凝。与 dPT 相比，dFiix-PT 始终能获得更好的结果。
在 1:1156 的高度稀释 TP 下，dFiix-PT 可用于测量所有在治疗浓度下测试的药物，除了达比加群酯。dPT 也能达到同样的效果，但需要两种 TP 稀释（1:750 和 1:300）。dFiix-PT 在 1:1156 下可以评估华法林的抗凝效果，PT 比值与国际标准化比值相同。使用六种不同的 TP 得到了相似的结果，但其中两种敏感性较低。在患者样本中，两种稀释 PT 检测方法都可以准确测量达比加群酯、利伐沙班和阿哌沙班，但 dFiix-PT 与特定检测方法之间的相关性始终优于 dPT。
单一稀释 TP 的 dFiix-PT 可能适用于评估华法林、达比加群酯、利伐沙班、阿哌沙班、肝素和依诺肝素的抗凝效果。
