Triplett D A
Department of Pathology, Ball Memorial Hospital, Muncie, IN.
Ric Clin Lab. 1989 Oct-Dec;19(4):379-89. doi: 10.1007/BF02871829.
The lupus anticoagulant may be defined as an immunoglobulin (IgG, IgM or both) which interferes with one or more of the in vitro phospholipid-dependent tests of coagulation. For many years, lupus anticoagulants were regarded as a laboratory nuisance; consequently, reagents were often selected on the basis of insensitivity to lupus anticoagulants. Recently, lupus anticoagulants have been associated with a variety of clinical conditions including recurrent thromboembolic events (both arterial and venous), obstetrical complications including fetal death and spontaneous abortion, and a variety of hematologic and neurologic complications. As a result, many laboratories are now being asked to identify the presence of lupus anticoagulants in selected patient populations. In addition to assays for lupus anticoagulants, there are immunologic assays designed to detect phospholipid antibodies using solid phase systems (RIA or ELISA). A variety of screening tests have been designed to enhance sensitivity to lupus anticoagulants. Test systems with decreased amounts of phospholipid (phosphatidylserine) appear to be most sensitive to lupus anticoagulants. Of the various tests used, the activated partial thromboplastin time (APTT) appears to be most sensitive. The sensitivity of any screening test system is inversely proportional to the residual platelets in the patient sample. APTT reagents differ widely in their sensitivity to lupus anticoagulants. The dilute Russell viper venom time is also highly dependent on the choice and concentration of phospholipid with respect to its sensitivity. Once an abnormality of a screening test has been identified, it is necessary to prove the abnormal result is due to the presence of an inhibitor. This step in the diagnosis may utilize either mixing studies or plasma agarose gels. The final step in the diagnosis of lupus anticoagulants is the demonstration of phospholipid specificity of the inhibitor. Two approaches have been utilized: 1. test systems designed to enhance anticoagulant effect (phospholipid-depleted), and 2. test systems with increased or altered phospholipids which will bypass or neutralize the anticoagulant.
狼疮抗凝物可定义为一种免疫球蛋白（IgG、IgM 或两者兼有），它会干扰一项或多项体外磷脂依赖性凝血试验。多年来，狼疮抗凝物一直被视为实验室中的麻烦因素；因此，试剂的选择通常基于对狼疮抗凝物不敏感。最近，狼疮抗凝物已与多种临床情况相关，包括复发性血栓栓塞事件（动脉和静脉）、产科并发症（包括胎儿死亡和自然流产）以及多种血液学和神经学并发症。因此，现在许多实验室被要求在特定患者群体中检测狼疮抗凝物的存在。除了狼疮抗凝物检测外，还有使用固相系统（放射免疫分析或酶联免疫吸附测定）检测磷脂抗体的免疫测定。已设计了多种筛查试验以提高对狼疮抗凝物的敏感性。磷脂（磷脂酰丝氨酸）含量降低的试验系统似乎对狼疮抗凝物最敏感。在使用的各种试验中，活化部分凝血活酶时间（APTT）似乎最敏感。任何筛查试验系统的敏感性与患者样本中的残余血小板成反比。APTT 试剂对狼疮抗凝物的敏感性差异很大。稀释的蝰蛇毒时间在敏感性方面也高度依赖于磷脂的选择和浓度。一旦筛查试验出现异常，就有必要证明异常结果是由抑制剂的存在引起的。诊断的这一步骤可采用混合试验或血浆琼脂糖凝胶法。狼疮抗凝物诊断的最后一步是证明抑制剂的磷脂特异性。已采用两种方法：1. 旨在增强抗凝作用（磷脂缺乏）的试验系统，以及 2. 具有增加或改变的磷脂以绕过或中和抗凝剂的试验系统。
