This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Physiology
Increased PT and Normal aPTT are found in which of the following? 
Select and explain. 
A. Von Willibrand's disease, B. Factor 7 deficiency, C. Factor 8 deficiency, D. Thrombin deficiency
B: Factor 7 deficiency
Answer: B: Factor 7 deficiency 
Explanation: The prothrombin time (PT) is prolonged in factor VII (FVII) deficiency and the international normalized ratio (INR) is elevated. The activated paial thromboplastin time (aPTT) is within the reference range in isolated factor VII deficiency. Prothrombin time (PT) is within reference range in von Willebrand disease. The aPTT will be outside of the reference range. A prolonged aPTT and a normal PT can be seen in factor 8 deficiency. Prothrombin (Factor II) is the precursor form of thrombin. PT and aPTT are prolonged in patients with factor II deficiency.