Which is most likely to be increased in Vit K deficiency:

Answer is B (P.T.): Although PT and PTT both will he affected PT is the single best answer as explained below. Therefore both intrinsic & extrinsic mechanisms of the coagulation cascade are affected. (Refer previous questions) PT & PTT both will be prolonged. However, factor VII has sho t1/2 & so PT is the first to be prolonged (even in mild vit. K deficiency) Later, factors II, IX & X will also fall, causing PTT to be prolonged. PT is thus the better choice out of PT and PTT