DIRECT ASSAY OF VITAMIN-B(1), VITAMIN-B(2), AND VITAMIN-B(6) IN HOSPITALIZED-PATIENTS - RELATIONSHIP TO LEVEL OF INTAKE

High-performance liquid chromatography assays for vitamins B1 by erythrocyte thiamine pyrophosphate, B2 by plasma and urinary riboflavin, and B-6, by plasma pyridoxal phosphate and urinary pyridoxic acid were used to evaluate the B2 vitamin status of hospitalized patients. Over an intake range of up to 3.4 mg of thiamine per day and up to 4.1 mg of riboflavin per day, erythrocyte thiamine pyrophosphate and urine and plasma riboflavin increased proportionately with intake. There was no relationship between B-6 intake and blood levels. Rather, a constant blood level was maintained with an intake range of 0.5 to 4 mg/d, and urinary pyridoxic acid showed a linear increase proportionate to intake. There were extremely variable blood and urine concentrations of B vitamins noted in our patient population.