Lupus Anticoagulant: The Misnamed Antibody That Looks Like a Bleeding Risk but Causes Clots
A blood test says your clotting time is prolonged, which normally signals a bleeding tendency. But in this case, the opposite is true: you're actually at a significantly higher risk of developing blood clots. That is the central, counterintuitive reality of lupus anticoagulant. It slows clotting down in a test tube while accelerating dangerous clot formation inside the body. The name is a misnomer on two counts. It has nothing specifically to do with lupus in most cases, and it is not an anticoagulant. It is one of the strongest laboratory predictors of thrombosis and pregnancy complications in medicine. Understanding what lupus anticoagulant actually is, how it's detected, and why the testing is so surprisingly unreliable matters if you or someone you know has been flagged for it.