What's circulating anticoagulant disorder?

A blood abnormality. It is a substance in the blood, usually an antibody, that interferes with the tests that analyze of ability of blood to clot. The most common is an anti-phospholipid antibody, or lupus anticoagulant, which actually makes clotting more likely. There are other antibodies that can make blood not clot (acquired hemophilia, etc.) drugs that prevent clotting are also "circulating" anticoagulants.