This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: FMGE 2018, Subject name: Medicine
True for von-willebrand disease 
Select and explain. 
A. Normal paial thromboplastin time, B. Decreased platelets, C. Normal prothrombin time, D. Normal bleeding time
C: Normal prothrombin time
Answer: C: Normal prothrombin time 
Explanation: VW factor- On trauma leads to formation of platelet plug at the site- Extrinsic pathway is activated (V, VII) - Intrinsic pathway is activated (VIII, etc) -Fibrin Fibrin insoluble Platelet plug is tested by bleeding time Extrinsic pathway is tested by prothrombin time (PT) Intrinsic pathway is tested by aPTT (activated paial PT) VWF plays a vital pa in the link between platelet plug + intrinsic factor Therefore, VWF if affected due to some reason then BT || & aPTT || but PT Normal IOC for VWD - RISTOCEIN aggregation test