The challenges of lupus anticoagulants.

The term "lupus anticoagulant" (LA) refers to a heterogeneous group of immunoglobulins behaving as acquired in vitro inhibitors of coagulation. These antibodies, namely anti-β2GPI and anti-prothrombin antibodies, induce the in vitro elongation of clotting time interfering with phospholipid-dependent coagulation cofactors. Positive LA is associated with thrombosis and pregnancy complications, providing one of the three laboratory criteria for the classification of the anti-phospholipid syndrome. LA is the strongest predictor of clinical events, especially when associated with other anti-phospholipid antibodies. Much more controversial is the risk conveyed by isolated and weak LA. LA detection is technically laborious, envisaging screening, mixing and confirming tests. Hopefully critical issues in LA detection, such as the interference of anticoagulants, will be overcome, in the next future.