This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bleeding disorder, Subject name: Pathology
PTT is prolonged in all except:- 
Select and explain. 
A. Hemophilia A, B. Von Willebrand disease, C. Christmas disease, D. ITP
D: ITP
Answer: D: ITP 
Explanation: aPTT is used to monitor the activity of Intrinsic pathway. (A.) Hemophilia (B.) Von Willebrand disease C.) Christmas disease (D.) ITP - Idiopathic Thrombocytopenic Purpura most common type of hemophilia is Hemophilia A . Hemophilia A - Factor VIII deficiency | | aPTT Associated with reduction in the half life of Factor VIII | | aPTT Factor IX deficiency || aPTT Disease associated with |platelets, not a clotting factor problem. Parameters affected in ITP a. Increase bleeding time* b. Decrease platelet count