- Abstract -

The differential diagnosis of a long APTT with a normal prothrombin time can be due to either a clotting factor deficiency or the presence of an inhibitor, which can be distinguished by using a plasma-mixing study. The various clotting factor deficiency, clinical bleeding following cardiac bypass surgery due to acquired factor V and thrombin antibodies and the evaluation of bleeding diathesis either a preoperative or postoperative setting will be discussed.