What is the relation between pt,ptt,lupas anticoagulant?

Lupus anticoagulant (also known as lupus antibody, LA, or lupus inhibitors) is an immunoglobulin[1] that binds to phospholipids and proteinsassociated with the cell membrane. Lupus anticoagulant is a misnomer as it is actually a prothrombotic agent. That is, presence of Lupus anticoagulant antibodies in living systems causes an increase in inappropriate blood clotting. Their name derives from their properties in vitro, since in laboratory tests, presence of these antibodies causes an increase in aPTT. It is speculated that the presence of the antibodies interferes with phospholipids utilized to induce in vitro coagulation.

In vivo, it is thought to interact with platelet membrane phospholipids, increasing adhesion and aggregation of platelets; thus its in vivo prothrombotic characteristics.