The term “lupus anticoagulant (LA)” identifies a form of antiphospholipid antibodies (aPLs) causing prolongation of clotting tests in a phospholipid concentration-dependent manner. LA is one of the laboratory criteria identified in patients with antiphospholipid (antibody) syndrome (APS). The presence of LA in patients with APS represents a significant risk factor for both thrombosis and pregnancy morbidity. There have been several reports of similarities between some of the pathophysiological features of COVID-19 and APS, in particular the most severe form, catastrophic APS. There have also been many reports identifying various aPLs, including LA, in COVID-19 patients. Accordingly, a very pertinent question arises: “Is LA a feature of COVID-19 pathology?” In this review, we critically appraise the literature to help answer this question. We conclude that LA positivity is a feature of COVID-19, at least in some patients, and potentially those who are the sickest or have the most severe infection. However, many publications have failed to appropriately consider the many confounders to LA identification, being assessed using clot-based assays such as the dilute Russell viper venom time, the activated partial thromboplastin time (aPTT), and the silica clotting time. First, most patients hospitalized with COVID-19 are placed on anticoagulant therapy, and those with prior histories of thrombosis would possibly present to hospital already on anticoagulant therapy. All anticoagulants, including vitamin K antagonists, heparin (both unfractionated heparin and low-molecular-weight heparin), and direct oral anticoagulants affect these clot-based assays. Second, C-reactive protein (CRP) is highly elevated in COVID-19 patients, and also associated with severity. CRP can also lead to false-positive LA, particularly with the aPTT assay. Third, persistence of aPL positivity (including LA) is required to identify APS. Fourth, those at greatest risk of thrombosis due to aPL are those with highest titers or multiple positivity. Most publications either did not identify anticoagulation and/or CRP in their COVID-19 cohorts or did not seem to account for these as possible confounders for LA detection. Most publications did not assess for aPL persistence, and where persistence was checked, LA appeared to represent transient aPL. Finally, high titer aPL or multiple aPL positivity were in the minority of COVID-19 presentations. Thus, at least some of the reported LAs associated with COVID-19 are likely to be false positives, and the relationship between the detected aPL/LA and COVID-19-associated coagulopathy remains to be resolved using larger and better studies.

术语“狼疮抗凝剂 (LA)”是一种抗磷脂抗体 (aPL)，它以磷脂浓度依赖性方式导致凝血试验延长。LA 是在抗磷脂（抗体）综合征 (APS) 患者中确定的实验室标准之一。APS 患者存在 LA 是血栓形成和妊娠发病率的重要危险因素。关于 COVID-19 和 APS 的一些病理生理学特征，特别是最严重的形式，即灾难性 APS 之间的相似性，已有几篇报道。也有许多报告确定了 COVID-19 患者的各种 aPL，包括 LA。因此，出现了一个非常相关的问题：“洛杉矶是 COVID-19 病理学的一个特征吗？” 在这篇综述中，我们批判性地评估了文献以帮助回答这个问题。我们得出结论，LA 阳性是 COVID-19 的一个特征，至少在某些患者中，并且可能是那些病情最严重或感染最严重的患者。然而，许多出版物未能适当考虑 LA 鉴定的许多混杂因素，使用基于凝块的测定法进行评估，例如稀罗素毒蛇毒液时间、活化部分促凝血酶原激酶时间 (aPTT) 和二氧化硅凝血时间。首先，大多数因 COVID-19 住院的患者接受抗凝治疗，而有血栓病史的患者可能已经在医院接受抗凝治疗。所有抗凝剂，包括维生素 K 拮抗剂、肝素（普通肝素和低分子量肝素）和直接口服抗凝剂都会影响这些基于凝块的检测。第二，COVID-19 患者的 C 反应蛋白 (CRP) 高度升高，并且与严重程度有关。CRP 也可能导致假阳性 LA，尤其是在 aPTT 检测中。第三，识别 APS 需要持续 aPL 阳性（包括 LA）。第四，aPL 导致血栓形成风险最高的是那些具有最高滴度或多重阳性的人。大多数出版物要么没有在他们的 COVID-19 队列中发现抗凝和/或 CRP，要么似乎没有将这些作为 LA 检测的可能混杂因素。大多数出版物没有评估 aPL 的持久性，在检查持久性的地方，LA 似乎代表暂时性 aPL。最后，高滴度 aPL 或多 aPL 阳性是少数 COVID-19 表现。因此，