This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Haematology, Subject name: Pathology
Isolated rise in aPTT is seen in? 
Select and explain. 
A. Von Willibrand's disease, B. Factor 7 deficiency, C. Vitamin K deficiency, D. Anti phospholipid antibodies
D: Anti phospholipid antibodies
Answer: D: Anti phospholipid antibodies 
Explanation: Isolated rise of APTT are seen in APTT measures the activity of the intrinsic and common pathways of coagulation CAUSES Lupus anti-coagulant (anti-phospholipid syndrome) Heparin exposure Haemophilia A and B (Factor VIII and IX deficiency respectively) Factor XII deficiency Factor XI deficiency Contact factor deficiency e.g. pre-kallikrein (not clinically impoant) Aefactual (incorrect amount of blood in the tube) Ref Robbins 9/e pg 54