Bleeding disorder can be either due to a problem in primary hemostasis or secondary hemostasis. Primary hemostasis related bleeding disorder are due to problems with platelets – either reduced production, increased consumption or increased destruction. Secondary hemostasis related bleeding disorders are caused by problems with the clotting factors – either a deficiency or presence of an inhibitor against the clotting factor. aPTT and PT are investigations used to see how effective the clotting factors are at forming a clot. A prolonged aPTT or PT means that the person has a tendency to bleed.