Standardization of the measuring method for lupus anticoagulant (LA)

对狼疮抗凝血剂（LA）作为血栓形成的危险因素，其检测方法进行了规范化研究。在1500 x g下单次离心15分钟获得的血浆（残余血小板：小于3000 /uL）对LA测试非常有用，因为当残余血小板超过1200 /uL时，血浆中的LA活性会发生显著变化。另一方面，根据我们使用相同磷脂条件和二氧化硅或鞣花酸作为活化剂的APTT试剂对LA的活性的结果，APTT试剂对LA的敏感性取决于磷脂浓度而不是活化剂。在APTT交叉混合试验中，10%和20%比例的LA血浆和50%比例的因子VIII缺乏血浆或抑制剂阳性血浆产生最佳结果。因此，建议对患者血浆进行0、10、20、50、100% 5种不同混合比例的混合试验。

Standardization of the measuring method for lupus anticoagulant (LA), which is a risk factor of thrombosis, was investigated. The plasma (residual platelets: less than 3,000/uL) obtained by single centrifugation at 1500 x g for 15 minutes, is quite useful for LA tests, because LA activity was significantly changed in plasma with more than 1,200/uL of residual platelets. On the other hand, the sensitivity of APTT reagents for LA is dependent on phospholipid concentration and not the activator, according to our results of LA activity using APTT reagents with same phospholipid condition and silica or ellagic acid as a activator. In an APTT cross-mixing test, 10% and 20% ratio of LA plasma and a 50% ratio of factor VIII deficient plasma or inhibitor positive plasma produced optimum results. Therefore, it is recommended to carry out the mixing test on 5 different mixing ratios of 0, 10, 20, 50, 100% of patient plasma.