A sequential, solid-phase assay for biotin in physiologic fluids that correlates with expected biotin status

Interest in accurate measurement of biotin concentrations in plasma and urine has been stimulated by recent advances in the understanding of biotin-responsive inborn errors of metabolism and by several reports describing acquired biotin deficiency during parenteral alimentation. This paper presents a biotin assay utilizing radiolabeled avidin in a sequential, solid-phase method; the assay has increased sensitivity compared to previous methods (≥10 fmol/tube), correlates with expected trends in biotin concentrations in blood and urine in a rat model of biotin deficiency, and can utilize commercially available radiolabeled avidin.