Haemostasis Research Unit, Department of Haematology, University College London, London, UK.
University of Sao Paulo, Sao Paulo, Brazil.
J Thromb Haemost. 2019 Dec;17(12):2069-2080. doi: 10.1111/jth.14596. Epub 2019 Sep 8.
Variability remains a challenge in lupus anticoagulant (LA) testing.
To validate LA test performance between Antiphospholipid Syndrome Alliance for Clinical Trials and International Networking (APS ACTION) Core laboratories and examine agreement in LA status between Core and local/hospital laboratories contributing patients to this prospective registry.
Five Core laboratories used the same reagents, analyzer type, protocols, and characterized samples for LA validation. Non-anticoagulated registry samples were retested at the corresponding regional Core laboratories and anticoagulated samples at a single Core laboratory. Categorical agreement and discrepancies in LA status between Core and local/hospital laboratories were analyzed.
Clotting times for the reference/characterized plasmas used for normalized ratios were similar between Core laboratories (CV <4%); precision and agreement for LA positive/negative plasma were similar (all CV ≤5%) in the four laboratories that completed both parts of the validation exercise; 418 registry samples underwent LA testing. Agreement for LA positive/negative status between Core and local/hospital laboratories was observed in 87% (115/132) non-anticoagulated and 77% (183/237) anticoagulated samples. However, 28.7% (120/418) of samples showed discordance between the Core and local/hospital laboratories or equivocal LA results. Some of the results of the local/hospital laboratories might have been unreliable in 24.7% (41/166) and 23% (58/252) of the total non-anticoagulated and anticoagulated samples, respectively. Equivocal results by the Core laboratory might have also contributed to discordance.
Laboratories can achieve good agreement in LA performance by use of the same reagents, analyzer type, and protocols. The standardized Core laboratory results underpin accurate interpretation of APS ACTION clinical data.
狼疮抗凝物（LA）检测仍然存在变异性问题。
验证 Antiphospholipid Syndrome Alliance for Clinical Trials and International Networking（APS ACTION）核心实验室之间的 LA 检测性能，并检查为该前瞻性登记处提供患者的核心和当地/医院实验室之间 LA 状态的一致性。
五个核心实验室使用相同的试剂、分析仪类型、方案和特征化样本进行 LA 验证。未抗凝的登记样本在相应的区域核心实验室重新检测，抗凝样本在一个核心实验室检测。分析核心和当地/医院实验室之间 LA 状态的分类一致性和差异。
用于归一化比值的参考/特征化血浆的凝固时间在核心实验室之间相似（CV<4%）；在完成验证工作两部分的四个实验室中，LA 阳性/阴性血浆的精密度和一致性相似（所有 CV≤5%）；418 个登记样本进行了 LA 检测。在未抗凝的样本中（115/132）和抗凝的样本中（183/237）观察到核心和当地/医院实验室之间 LA 阳性/阴性状态的一致性分别为 87%和 77%。然而，418 个样本中有 28.7%（120/418）显示出核心和当地/医院实验室之间的不一致或 LA 结果不确定。在未抗凝的样本（166/418）和抗凝的样本（252/58）中，分别有 24.7%和 23%的样本的当地/医院实验室结果可能不可靠。核心实验室的不确定结果也可能导致不一致。
通过使用相同的试剂、分析仪类型和方案，实验室可以在 LA 性能方面实现良好的一致性。标准化的核心实验室结果为 APS ACTION 临床数据的准确解释提供了基础。
