Administering folic acid may obscure pernicious anemia. In patients receiving total parenteral nutrition (TPN), routine supplementation with both fat-soluble and water-soluble vitamins is recommended to prevent deficiency states and to obviate the need to speculate on individual vitamin status. Daily vitamin requirements must be calculated to avoid over dosage and toxic effects, especially with regards to vitamins A & D and particularly in pediatric patients. In patients for whom total parenteral nutrition is continued for prolonged periods (months or years), periodic monitoring of blood vitamin levels should be considered. To prevent excessive excretion of water-soluble vitamins and for reasons of...