Divisions of Laboratory Medicine and Hematology, Children's National Health System, Washington, District of Columbia.
Departments of Pediatrics and Pathology, George Washington University School of Medicine and Health Sciences, Washington, District of Columbia.
Int J Lab Hematol. 2019 Feb;41(1):80-86. doi: 10.1111/ijlh.12925. Epub 2018 Sep 8.
The dilute Russell viper venom time (dRVVT) detects lupus anticoagulant (LA). International Society for Thrombosis and Haemostasis (ISTH) guidelines specify positivity criteria, which differ from the assay manufacturer's criteria.
Two years of dRVVT testing at our institution were reviewed. For patients with prolonged dRVVT screening times, we evaluated dRVVT results by ISTH and manufacturer's criteria and correlated with the results of other antiphospholipid syndrome (APS) testing (LA-sensitive activated partial thromboplastin time and antiphospholipid antibodies) and with history of thromboembolism and other APS manifestations.
Approximately one-fifth of dRVVTs exhibited a prolonged screening time. Among first prolonged dRVVTs, 35% were positive by both ISTH and manufacturer criteria, 44% met neither criteria, and 20% were equivocal (positive by only ISTH or manufacturer). Positivity by ISTH guidelines alone correlated better with other positive APS tests than manufacturer criteria positivity. Positive dRVVTs by both criteria correlated even more strongly with other positive APS assays. We investigated the likelihood of eventual APS diagnosis depending on the testing indication. No patient tested for LA solely for prolonged screening aPTT was subsequently diagnosed with APS. In patients with thrombosis, prolonged dRVVT clotting time not meeting both ISTH and manufacturer criteria was rarely associated with eventual APS diagnosis.
We examined the correlation of dRVVT results with other APS testing and clinical outcomes. Interpretation method impacted how dRVVT results related to other APS testing, and, in limited data, to clinical findings. Patients with prolonged dRVVTs meeting only one set of positivity criteria rarely received an APS diagnosis.
稀释 Russell 蝰蛇 venom 时间（dRVVT）检测狼疮抗凝物（LA）。国际血栓与止血学会（ISTH）指南规定了阳性标准，与检测试剂制造商的标准不同。
我们回顾了本机构两年的 dRVVT 检测结果。对于 dRVVT 筛查时间延长的患者，我们根据 ISTH 和制造商的标准评估 dRVVT 结果，并与其他抗磷脂综合征（APS）检测（LA 敏感的活化部分凝血活酶时间和抗磷脂抗体）的结果以及血栓栓塞和其他 APS 表现的病史相关联。
大约五分之一的 dRVVT 显示筛查时间延长。在首次延长的 dRVVT 中，35%符合 ISTH 和制造商标准的阳性标准，44%不符合任何标准，20%为不确定（仅符合 ISTH 或制造商标准的阳性）。ISTH 指南单独规定的阳性标准与其他阳性 APS 检测的相关性优于制造商标准阳性。符合两项标准的阳性 dRVVT 与其他阳性 APS 检测的相关性更强。我们根据检测指征调查了最终 APS 诊断的可能性。仅因延长的筛查 aPTT 而检测 LA 的患者中，无一人随后被诊断为 APS。在有血栓形成的患者中，不符合 ISTH 和制造商标准的延长 dRVVT 凝血时间很少与最终 APS 诊断相关。
我们检查了 dRVVT 结果与其他 APS 检测和临床结果的相关性。解释方法影响了 dRVVT 结果与其他 APS 检测的关系，在有限的数据中，还影响了临床发现。仅符合一套阳性标准的延长 dRVVT 患者很少被诊断为 APS。
