Blood clotting is the mean by which the body protects the integrity of blood vessels. Clinical tests, or clotting assays, are regularly performed to characterize bleeding disorders such as hemophilia A and B but are currently limited due to interferences present in the blood of some patients. There is a pressing need to develop a coagulation assay that is reproducible, reliable and that can be used for patients containing Lupus agents. Based on several decades of basic research in the regulation of the prothrombinase complex, which consists of a serine protease, factor Xa (FXa), and a protein cofactor, factor Va (FVa) by water soluble Phosphatidyl Serine (PS), we have developed and started to study an exciting novel PS compound containing saturated diacyl chains of only six carbons (C6PS). Using this soluble PS molecule, we have been able under ceratin circumstances to bypass the limitations caused by lupus anticoagulants and we have already obtained an US Patent for this novel reagent. Successful development of this assay will decrease misdiagnoses of bleeding disorders and will remove the need for expensive subsequent testing.