Increased Prothrombin time results from deficiency of ?

Ans. is 'b' i.e., FibrinogenTests used to evaluate different aspects of hemostasis :i) Bleeding time It 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.iii) Paial thromboplastin time (PTT) This assay tests the intrinsic and common coagulation pathways.So, a prolonged PTT. can results from the deficiency of factor V, VIII, IX, X, XI, XII, prothrombin or fibrinogen.iv) Thrombin timeIt is the time taken for clotting to occur when thrombin is added to the plasma.It tests the conversion of fibrinogen to fibrin and depends on adequate fibrinogen level.Prolonged thrombin time results from decreased level of fibrinogen.