Moore G W, Tugnait S, Savidge G F
Centre for Haemostasis and Thrombosis (Haemophilia Reference Centre), St Thomas' Hospital, London, UK.
Br J Biomed Sci. 2005;62(3):127-32. doi: 10.1080/09674845.2005.11732699.
The dilute Russell's viper venom time (DRVVT) is one of the most widely used assays to detect lupus anticoagulants (LAs). Variation in diagnostic performance exists between DRVVT reagents from various manufacturers due to a variety of factors such as antibody heterogeneity, reagent phospholipid composition, venom heterogeneity, assay methodology and analytical technique. Recently, a new-generation DRVVT assay system has become available that utilises frozen reagents and controls that offer potential benefits to the diagnostic laboratory in terms of reagent quality and convenience of use. This study evaluates the diagnostic and analytical performance of these CryoCheck reagents and controls on a commonly employed automated coagulation analyser, the Sysmex CA 1500. Sensitivity is assessed by analysis of 60 samples shown to contain LAs by combinations of an alternative DRVVT, LA-sensitive dilute activated partial thromboplastin time and activated seven lupus anticoagulant assay. Specificity is assessed using 30 samples negative for LA, eight plasmas from non-LA orally anticoagulated patients and also immunodepleted factor-deficient plasmas. The CryoCheck reagents generated comparable diagnostic performance data to that previously reported for other reagents. There was a marked improvement in sensitivity when the BCSH recommended percent correction of ratio calculation for assessment of phospholipid dependence was employed in place of the manufacturer suggested test/confirm ratio. Slightly better diagnostic performance was achieved when using a frozen pooled normal control in place of a lyophilised normal control to generate sample/control ratios, giving sensitivity, specificity, positive predictive and negative predictive values of 88.2%, 86.8%, 90% and 85.2%, respectively. The combination of CryoCheck reagents and the Sysmex CA 1500 analyser provides a sensitive and specific LA detection technique comparable to those currently available.
稀释蝰蛇毒时间（DRVVT）是检测狼疮抗凝物（LA）最常用的检测方法之一。由于抗体异质性、试剂磷脂组成、蛇毒异质性、检测方法和分析技术等多种因素，不同厂家的DRVVT试剂在诊断性能上存在差异。最近，一种新一代的DRVVT检测系统已经问世，它使用冷冻试剂和对照品，在试剂质量和使用便利性方面为诊断实验室带来了潜在的好处。本研究评估了这些CryoCheck试剂和对照品在常用的Sysmex CA 1500自动凝血分析仪上的诊断和分析性能。通过分析60份样本评估敏感性，这些样本通过另一种DRVVT、LA敏感的稀释活化部分凝血活酶时间和活化七狼疮抗凝物检测的组合显示含有LA。使用30份LA阴性样本、8份非LA口服抗凝患者的血浆以及免疫耗尽的因子缺乏血浆评估特异性。CryoCheck试剂产生的诊断性能数据与先前报道的其他试剂相当。当采用英国血液学标准委员会（BCSH）推荐的用于评估磷脂依赖性的比率计算校正百分比来代替制造商建议的检测/确认比率时，敏感性有显著提高。当使用冷冻混合正常对照品代替冻干正常对照品来生成样本/对照比率时，诊断性能略有提高，敏感性、特异性、阳性预测值和阴性预测值分别为88.2%、86.8%、90%和85.2%。CryoCheck试剂与Sysmex CA 1500分析仪的组合提供了一种与目前可用技术相当的敏感且特异的LA检测技术。
