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: Pathology
[{'content': 'Test for extrinsic and common coagulation pathway is ? \nSelect and explain. \nA. PT, B. aPTT, C. Bleeding time, D. Thrombin time', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., PTPatients with hemophilia have deficiency of factor VIII that results in prolonged PTT.Tests used to evaluate different aspects of hemostasis.i) Bleeding timeIt is not a test for coagulation rathers it tests the ability of the vessels to vasoconstrict and the platelets to form a hemostatic plug.It is the time taken for a standardized skin puncture to stop bleeding.Normal reference value is between 2-9 minutes.Prolongation generally indicates the defect in platelet number or function.ii) Prothrombin time (PT)This assay tests the extrinsic and common coagulation pathway.So, a Prolonged PT can result from deficiency of factor V, VII, X, prothrombin or fibrinogen.", 'role': 'assistant'}]