Feature of hemorrhagic disease of new born is?

Answer is A (Prolonged prothrombin time) Hemorrhagic disease of new born results from a deficiency of vitamin K. Prothrombin time is the single best laboratory test to detect vitamin K deficiency as vitamin k deficiency may present with isolated prolongation of PT Laboratory features of vitamin k deficiency (CMDT-2008) Both PT and PTT are prolonged but prolongation of PT is a more sensitive test to detect vitamin K deficiency than PTT - The PT is prolonged to a greater extent than PTT - With mild vitamin K deficiency only the PT is defective Fibrinogen level, Thrombin time and platlet count are not affected - CMDT