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': 'Hemophilia manifest clinically as a rise in - \nSelect and explain. \nA. APTT, B. PT, C. CT, D. FDP', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Patients with hemophilia have a deficiency of factor VIII that results in prolonged PTT.\nTests used to evaluate different aspects of hemostasis.\n(i)\xa0\xa0Bleeding time\n\nIt is not a test for coagulation rathers it tests the ability of the vessels to vasoconstrict and the platelets to form a hemostatic plug.\nIt is the time taken for a standardized skin puncture to stop bleeding.\nNormal reference value is between 2-9 minutes.\nProlongation generally indicates the defect in platelet number or function.\n\n(ii)\xa0Prothrombin time (PT)\n\nThis assay tests the extrinsic and common coagulation pathway.\nSo, a Prolonged PT can result from a deficiency of factor V, VII, X, prothrombin or fibrinogen.\n\n(iii)\xa0Partial thromboplastin time (PTT)\n\nThis assay tests the intrinsic and common coagulation pathways.\nSo, a prolonged PTT\xa0can result\xa0from the deficiency of factor V, VIII, IX, X, XI, XII, prothrombin or fibrinogen.\n\n(iv)\xa0Thrombin time\n\nIt is the time taken for clotting to occur when thrombin is added to the plasma.\nIt tests the conversion of fibrinogen to fibrin and depends on adequate fibrinogen level.\nProlonged thrombin time results from decreased level of fibrinogen.', 'role': 'assistant'}]