BACKGROUND & AIMS:
:Laboratory diagnosis of lupus anticoagulant (LA) is based on prolongation in at least one coagulation assay (diluted Russell's viper venom time - dRVVT or activated partial thromboplastin time - aPTT), which normalises after addition of phospholipids. Both assays may be influenced by anticoagulants and therefore LA should not be tested during warfarin or heparin treatment. It has been shown (primarily in vitro) that direct oral anticoagulants (DOACs - dabigatran [DAB], rivaroxaban [RIV] and apixaban [API]) may also influence LA testing. We tested the effects of DOACs on assays routinely used for the diagnosis of LA in patients treated with these drugs in a real-life setting. Plasma from patients with atrial fibrillation treated with DAB (n=30), RIV (n=20) and API (n=17) and not known to have LA were tested using dRVVT (LA-screen and LA-confirm, Life Diagnostics) and aPTT (PTT-LA, Diagnostica Stago and aPTT Actin FS, Siemens Healthcare Diagnostics) assays. According to the diagnostics algorithm, dRVVT and aPTT ratios of <1.2 were considered negative, ratios of >1.4 positive, while if the ratios were 1.2-1.4 LA could not be ruled out. Plasma concentrations varied between 8-172 µg/l for DAB, 8-437 µg/l for RIV and 36-178 µg/l for API. LA diagnosis was negative in only eight (27 %) plasma samples from patients treated with DAB, and in five (25 %) and four samples (24 %) from patients treated with RIV and API, respectively. LA Positivity (dRVVT and aPTT ratios >1.4) was found in 5 cases (17 %) among patients treated with DAB, in 10 cases (50 %) treated with RIV and in 7 cases (41 %) treated with API. A concentration-dependent effect of DOACs on dRVVT-based parameters was observed, particularly as regards DAB. At lower concentrations, RIV and API had only minor effects on the confirmatory tests (below 100 µg/l and 70 µg/l, respectively). Our results suggest that a risk of overestimation of LA detection is present in samples from patients treated with DOACs. Therefore, LA testing should not be performed during treatment with DOACs. Prolongation in confirmatory assays may be helpful for the recognition of false positivity, especially as regards DAB.
背景与目标:
:狼疮抗凝剂(LA)的实验室诊断基于至少一种凝血测定法的延长(稀释的罗素毒蛇毒时间-dRVVT或活化的部分凝血活酶时间-aPTT),在添加磷脂后即可恢复正常。两种测定均可能受抗凝剂影响,因此在华法林或肝素治疗期间不应测试LA。已显示(主要在体外)直接口服抗凝剂(DOAC-达比加群[DAB],利伐沙班[RIV]和阿哌沙班[API])也可能影响LA测试。我们在现实生活中用这些药物治疗的患者,测试了DOACs对常规用于诊断LA的测定的影响。使用dRVVT对DAB(n = 30),RIV(n = 20)和API(n = 17)治疗的房颤患者的血浆进行了dRVVT测试(LA-screen和LA-confirm,Life Diagnostics)和aPTT(PTT-LA,Diagnostica Stago和aPTT Actin FS,Siemens Healthcare Diagnostics)测定。根据诊断算法,dRVVT和aPTT比率<1.2被视为阴性,比率> 1.4呈阳性,而如果比率为1.2-1.4,则不能排除LA。血浆浓度在DAB的8-172 µg / l,RIV的8-437 µg / l和API的36-178 µg / l之间变化。在接受DAB治疗的患者血浆样本中,只有8(27%)的LA诊断为阴性,而接受RIV和API治疗的患者分别为5(25%)和4(24 %%)的LA诊断为阴性。在接受DAB治疗的患者中,有5例(17%)的LA阳性率(dRVVT和aPTT比> 1.4),通过RIV治疗的10例(50 %%)和通过API治疗的7例(41 %%)被发现。观察到DOAC对基于dRVVT的参数具有浓度依赖性,尤其是在DAB方面。在较低的浓度下,RIV和API对确认性测试的影响很小(分别低于100 µg / l和70 µg / l)。我们的结果表明,来自接受DOAC治疗的患者的样本中存在高估LA检测的风险。因此,在用DOAC治疗期间不应进行LA测试。确认试验的延长可能有助于识别假阳性,尤其是对于DAB。