Department of Clinical Biochemistry, Rigshospitalet, Copenhagen, Denmark.
Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Angelo Bianchi Bonomi Hemophilia and Thrombosis Center and Fondazione Luigi Villa, Milano, Italy.
Eur J Haematol. 2020 Jun;104(6):519-525. doi: 10.1111/ejh.13394. Epub 2020 Feb 27.
A common inquiry in coagulation laboratories is how to interpret an unexpected, isolated prolonged activated partial thromboplastin time (APTT). In this context, isolated means together with a normal prothrombin time (PT) and/or normal international normalized ratio (INR). This finding may lead to contact with laboratory doctors for further advice on a diagnostic strategy. Occasionally, the need for a diagnostic algorithm can be subacute, where surgery has to be postponed until an explanation for the isolated, prolonged APTT has been established. Activated partial thromboplastin time as a coagulation test was developed to monitor patients with hemophilia. Different APTT reagents display considerable differences in their sensitivity to deficiencies of coagulation factors. An isolated, prolonged APTT is seen in (a) individuals/patients with lupus anticoagulants, (b) patients in treatment with anticoagulants, mainly heparin, and (c) patients with deficiencies of specific coagulation factors. In this tutorial review, we summarize what may cause an isolated prolonged APTT and we present a simple diagnostic algorithm to differentiate between lupus anticoagulants (common) and factor deficiencies (rare). The identification of an isolated prolonged APTT as well as the underlying cause can be of the utmost importance in ensuring the correct therapeutic follow-up.
在凝血实验室中，经常会询问如何解释意外的、孤立的延长的活化部分凝血活酶时间（APTT）。在这种情况下，“孤立的”是指同时伴有正常的凝血酶原时间（PT）和/或正常的国际标准化比值（INR）。这一发现可能会导致与实验室医生联系，以进一步就诊断策略提供建议。偶尔，需要进行诊断性分析的情况可能是亚急性的，需要推迟手术，直到确定孤立延长的 APTT 的原因。活化部分凝血活酶时间作为一种凝血检测方法是为了监测血友病患者而开发的。不同的 APTT 试剂在对凝血因子缺乏的敏感性方面存在很大差异。孤立的、延长的 APTT 可见于：(a) 狼疮抗凝剂个体/患者，(b) 正在接受抗凝治疗的患者，主要是肝素，和 (c) 特定凝血因子缺乏的患者。在本教程综述中，我们总结了可能导致孤立延长的 APTT 的原因，并提出了一个简单的诊断性算法，以区分狼疮抗凝剂（常见）和因子缺乏症（罕见）。确定孤立延长的 APTT 及其潜在原因对于确保正确的治疗随访至关重要。
