An Approach to the Measurement of Lupus anticoagulant through a Case of Coronary Vasospastic Myocardial Infarction

Abstract

The antiphospholipid syndrome (APS) is one of the typical thrombosis-associated diseases and is diagnosed on the basis of clinical symptoms and laboratory data that indicate the presence of anti-cardiolipin antibody (aCL) and/or lupus anticoagulant (LA). Although criteria for the laboratory tests for the detection of aCL and LA had been proposed by the Scientific Standardization Committee of the International Society on Thrombosis and Haemostasis, these criteria have not necessarily been followed strictly. Thus, there are certain discrepancies among institutions in terms of accuracy of diagnosis and sensitivity to detect aCL and LA. In fact, we have recently experienced this sort of discrepancy between the data of tests conducted on a patient, in which the presence of LA was negative in a test performed by a commercially available blood test laboratory, whereas it was positive in the other conducted in our own hospital. Techniques employed in individual laboratories may differ : namely techniques for platelet deletion from plasma ; preparation of mixtures of normal and the patient's plasmas for the study of inhibitor (s) and the number of tests to be carried out for the detection of LA. These differences may well account for the discrepancy, and thus should be taken into consideration for the diagnosis of APS clinically.