Vitamin K deficiency thus activate) certain enzymes involved in coagulation: Factors II, VII, IX, X, and protein C and protein S. Inability to activate the clotting cascade via these factors leads to the bleeding symptoms mentioned above. Notably, when one examines the lab values in Vitamin K deficiency [see below] the prothrombin time is elevated, but the partial thromboplastin time is normal or only mildly prolonged. This may seem counterintuitive given that the deficiency leads to decreased activity in factors of both the intrinsic pathway (F-IX) which is monitored by PTT, as well as the extrinsic pathway (F-VII) which is monitored by PT.
Vitamin B12 deficiency anemia II deficiency, or intestinal bacterial overgrowth are present. Low levels of serum vitamin B may be caused by other factors than B deficiency, such as folate deficiency, pregnancy, oral contraceptive use, haptocorrin deficiency, and myeloma. The presence of antibodies to gastric parietal cells and intrinsic factor is common in PA. Parietal cell antibodies are found in other autoimmune disorders and also in up to 10% of healthy individuals, making the test nonspecific. However, around 85% of PA patients have parietal cell antibodies, which means they are a sensitive marker for the disease. Intrinsic factor antibodies are much less sensitive than