IntroductionThorough assessment of the antiphospholipid syndrome (APS) includes retesting of positive antiphospholipid antibody (aPL) tests after at least 12 weeks, and a full antiphospholipid antibody profile. To what extent this work‐up is done in clinical practice is unknown.MethodsData on 25 116 in‐ and out‐hospital patients tested for the presence of lupus anticoagulant (LA), the aPL which most strongly correlates with thrombosis, was extracted from the laboratory information system of the only laboratory that performs LA tests in the Capital Region, Denmark. We estimated fraction of repeated tests, tests repeated within the recommended time span, and fraction with a full aPL profile.ResultsOut of 25 116 patients, 843 were positive for LA (3.3%), and 3948 results were inconclusive (16%). Only 51% (95% CI of the proportion: 48%–54%) (n = 431) of positive tests were repeated. The proportion of inconclusive LA test results increased from 13% (12%–15%) in 2009 to 20% (19%–22%) in 2020. Out of the positive tests repeated within the first year, only 60/353 (17%; 13%–21%) were repeated within 12–16 weeks; 177/353 (50%; 45%–55%) were re‐tested within the first 12 weeks of first positive test result. The proportion of patients with a full antiphospholipid antibody profile increased from 161/1978 (8%) in 2010 to 1041/1978 (43%) in 2020.ConclusionWe found several issues with the laboratory workup of APS. This indicates a need for increased awareness of comprehensive laboratory assessment of possible APS as well as a closer collaboration between the laboratory and clinicians.

中文翻译：

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抗磷脂综合征的实验室评估：实验室数据

简介抗磷脂综合征 (APS) 的全面评估包括至少 12 周后重新测试阳性抗磷脂抗体 (aPL) 测试，以及完整的抗磷脂抗体谱。这项检查在临床实践中进行到什么程度尚不清楚。方法对 25 116 名院内和院外患者进行了狼疮抗凝物 (LA) 检测，检测其是否存在狼疮抗凝物 (LA)（与血栓形成最相关的 aPL），数据提取自丹麦首都地区唯一进行 LA 测试的实验室的实验室信息系统。我们估计了重复测试的分数、在建议时间范围内重复测试的分数以及完整 aPL 概况的分数。结果 在 25 116 名患者中，843 例 LA 呈阳性 (3.3%)，3948 例结果不确定 (16%)。仅 51%（该比例的 95% CI：48%–54%）（n= 431) 的阳性测试被重复。 LA 检测结果不确定的比例从 2009 年的 13% (12%–15%) 增加到 2020 年的 20% (19%–22%)。在第一年内重复的阳性检测中，只有 60/353 (17 %; 13%–21%) 在 12–16 周内重复； 177/353 (50%; 45%–55%) 在首次检测结果呈阳性后的前 12 周内重新进行了检测。具有完整抗磷脂抗体谱的患者比例从 2010 年的 161/1978 (8%) 增加到 2020 年的 1041/1978 (43%)。结论我们发现 APS 的实验室检查存在几个问题。这表明需要提高对可能发生 APS 的综合实验室评估的认识，以及实验室和临床医生之间更密切的合作。