quality:corruption
Signs and symptoms

Notably, when one examines the lab values in Vitamin K deficiency the prothrombin time is elevated, but the partial thromboplastin time is normal or only mildly prolonged. The deficiency leads to decreased activity in the intrinsic pathway (F-IX) factors, monitored by PTT, and the extrinsic pathway (F-VII) which PT monitors. However, factor VII has the shortest half-life of all the factors carboxylated by vitamin K; therefore, when deficient, it is the PT that rises first, since the activated Factor VII is the first to "disappear." In later stages of deficiency, the other factors (which have longer half-lives) can "catch up," and the PTT also rises.