<prompt> Factor IX deficiency results in increased -PT Prothrombin TimePTT Partial thromboplastin timeBT Bleeding TimeTT Thrombin time  <response>: Ans. is b i.e., PTT Partial thromboplastin time o Partial thromboplastin time PTT: It tests the intrinsic and common coagulation pathways. So, a prolonged PTT can results from deficiency of factor V, VIII factor VIIIc, Von willebrand factor, IX, X, XI, XII, prothrombin or fibrinogen.o Prothrombin time PT: It tests the extrinsic and common coagulation pathways. So, a prolonged PT can results from deficiency offactor V, VII, X, prothrombin or fibrinogen. Thus in common coagulation pathway defect both PT and PTT are elevatedo Activated clotting time clotting time: It also tests the intrinsic and common coagulation system. So it is prolonged in deficiency of same factors as for prolonged PTT.o Thrombin time : It tests the conversion of fibrinogen to fibrin and is elevated in fibrinogen deficiency.o Bleeding time : this altered in platelet dysfunction. 