It is important to note that while typical testing for hemophilia patients shows a prolonged activated partial thromboplastin time (aPTT) with a normal prothrombin time (PT) [5], most aPTT reagents may not detect mild deficiencies in coagulation factors (30–50% of normal), as they are more sensitive to severe deficiencies (10–20%). Here, F2 is linked to hemophilia.