After confirming that preanaytical factors are not responsible for the prolonged coagulation test(s) and there is no known medical condition, such as liver disease, vitamin K deficiency, or DIC that is causing the prolongation, a mixing study may be ordered to detect the presence of a possible factor deficiency or coagulation inhibitor.
Knowledge of the coagulation factors that are monitored by the PT and aPTT tests is necessary to choose the appropriate mixing study(ies) that should be performed.