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
[{'content': 'Extrinsic system of coagulation is checked by:March 2010 \nSelect and explain. \nA. aPTT, B. PT, C. BT, D. PTT', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. B: PTBleeding Time (Normal:1-6 min.) is for checking the number of platelets. It is prolonged by lack of platelets. Clotting time (Normal:6-10 min.) varies widely depending upon the method employed, so discarded nowadays. Instead measurements of clotting factors are being done.aPTT/PTT is employed for assessing intrinsic system.Prothrombin time (Normal:12 sec.) gives an good indication of concentration of prothrombin in the blood. Extrinsic pathway is assessed.', 'role': 'assistant'}]