Complete blood count (CBC) (including platelets)(29,32–35) Peripheral blood smear(29,32,34,35) Prothrombin time (PT)/International normalized ratio (INR)(29,32–35) Activated partial thromboplastin time (aPTT)(29,32–35) Fibrinogen(29,32,34,35) von Willebrand studies(33–35) Blood group (for interpretation of von Willebrand levels)(33,34) Factor VIII level(33–35) Factor IX level(33–35) Liver function tests (for secondary platelet dysfunction)(29,34) Renal function tests (for secondary platelet dysfunction)(29,34)