The Lupus Anticoagulant (LA) test is a blood coagulation test used to identify autoimmune antibodies that disrupt the clotting process in a laboratory setting. These antibodies, which are part of the antiphospholipid syndrome (APS), target phospholipids or proteins bound to them and are associated with an increased risk of thrombosis (blood clots in vessels) and pregnancy complications such as recurrent miscarriages or preterm delivery. Despite its name, LA is not primarily seen in patients with systemic lupus erythematosus (SLE), but is also present in APS and other autoimmune diseases. LA is diagnosed using functional tests such as the dilute Russell’s viper venom time (dRVVT) or modified activated partial thromboplastin time (APTT), which show prolonged clotting times. Confirmatory tests, such as adding phospholipids, are used to verify the antibody’s phospholipid dependence. Interpretation of results requires caution because anticoagulant medications (e.g., warfarin) or infections can interfere with the outcomes. A definitive diagnosis of LA depends on its persistent presence in two tests at least 12 weeks apart, along with clinical symptoms (such as thrombosis or pregnancy complications). This test plays a key role in the preventive management of high-risk patients and the prescription of antithrombotic treatments.
