The incidence and impact of lupus anticoagulants among patients in the intensive care unit.

oagulation abnormalities are commonly encountered in critically ill patients. Thus, intensivists are often challenged by the finding of prolonged activated partial thromboplastin time (APTT) in the setting of a normal international normalize ratio (INR). Potential causes of this presentation include heparin, a specific coagulation factor inhibitor, or a non-specific inhibitor, also known as a lupus anticoagulant (LA). Lupus anticoagulants are one of the 2 cardinal types of antiphospholipid antibodies. The presence of an antiphospholipid antibody (APA) in concern with venous or arterial thrombosis or recurrent pregnancy loss defines the antiphospholipid antibody syndrome (APS).1 Antiphospholipid antibody syndrome is either identified using a coagulation assay for LA or by detection of an anticardiolipin antibody using a specific enzyme-linked immunosorbent assay.1 Lupus anticoagulants are antibodies that interfere with one or more phospholipid-dependent activated partial throm-boplastin assays.2 Other APA have been identified; these include antibodies directed against pro-thrombin or one a variety of anionic cell surface glycoproteins. Despite their name LA antibody are associated with thromboembolic events rather than clinical bleeding.1 Approximately one third of individual with LA suffers with arterial or venous thrombosis or recurrent pregnancy loss.