ABSTRACT
Vitamin K is one of the fat-soluble vitamins. A vitamin K deficiency is associated with a prolonged prothrombin time and ecchymoses. Breast-fed infants commonly have a very poor vitamin K status with low plasma prothrombin concentrations. In the human, vitamin K deficiency is often associated with the use of anti-coagulants which inhibit vitamin K epoxide reductase. Traditional methods for assessing vitamin K status, such as prothrombin tests, and activated partial thromboplastin time, are relatively insensitive for detecting a subclincial vitamin K deficiency. Serum vitamin K testing has been suggested for individuals with osteoporosis, or in women who have relatives with osteoporosis. The most common causes of vitamin K deficiency are malnutrition, antibiotic therapy, oral anticoagulants, and infant hemorrhagic disease. The blood clotting process involves the participation of a number of vitamin K dependent plasma proteins.
