What is lupus anticoagulant?

Lupus anticoagulant is a type of antiphospholipid antibody. Antibodies are proteins typically produced by the immune system to target and protect against harmful entities. In some cases, the immune system can malfunction, producing antibodies which target and attack the body’s own cells. Lupus anticoagulant targets phospholipids which are an important component of cell membranes. This increases the likelihood of a blood clot.

Lupus anticoagulant was first detected in systemic lupus erythematosus (SLE) patients but it is not only found in this autoimmune condition. It may be a contributing factor to clot formation, foetal loss or a longer result from the Activated Partial Thromboplastin Time (aPTT) test. Lupus anticoagulant cannot be detected using one single test but affects the results of several clotting tests.

The aPTT test is used to detect abnormal blood clotting characteristics. Blood clotting occurs via two pathways, the intrinsic and extrinsic. The aPTT test measures the speed of blood clotting via the intrinsic pathway and in conjunction with a test for the extrinsic pathway, Prothrombin Time (PT), can give an indication of proper or improper clotting. The international normalised ratio (INR) test which measures the time it takes to form a clot and the dilute Russell viper venom time (DRVVT) can be used alongside the aPTT and PT tests to investigate the presence of lupus anticoagulant.

Why take the test?

This is a comprehensive check for lupus anticoagulant using the aPTT, PT, INR and DRVVT tests and may be used to help investigate blood clots or foetal loss.