Vitamin K deficiency in children pre-bone marrow transplantation.

This study examined the prevalence of vitamin K deficiency in children pre-bone marrow transplantation (BMT). Vitamin K status was measured by the PIVKA-II assay and prothrombin times. Blood samples were obtained before vitamin-containing TPN was infused. Results indicated that eight of 26 patients (31%) were vitamin K deficient; four cases were attributed to drug antagonism (phenytoin) and four were due to inadequate vitamin K intake, synthesis or malabsorption. Only one patient had a prolonged prothrombin time. Prothrombin time, in our study, is shown to be an ineffective screening tool to determine vitamin K status. All patients receiving phenytoin and chemotherapy are at increased risk of vitamin K deficiency.