Biotin Supplementation and Ferritin Levels
Biotin supplementation does not appear to change circulating ferritin concentration in controlled supplementation studies measuring iron indices directly [1]. Biotin can interfere with some laboratory immunoassays that use biotin-streptavidin technology, which can produce incorrect ferritin results in certain assay platforms [2], [3].
Direct Effect on Ferritin Concentration
A 30-day randomized intervention in healthy adults comparing organically versus synthetically derived multivitamin/mineral supplements reported no changes in ferritin concentrations after supplementation [1]. In that study, measured postingestion profiles included iron and ferritin as analytes with no observed group differences [1].
Laboratory Test Interference (Assay Artifact)
Biotin supplementation can interfere with immunoassays that incorporate biotin and streptavidin components, which can yield falsely high or falsely low results depending on assay design [2]. A crossover trial evaluating biotin’s effect on multiple hormone and nonhormone assays after 7 days of 10 mg/day biotin reported interference affecting ferritin testing among other analytes [2]. The NIH Office of Dietary Supplements notes that falsely high or falsely low laboratory results can occur with high biotin intakes due to assay interference [3].
Practical Clinical Implication for Ferritin Testing
Ferritin results obtained during periods of biotin supplementation may be unreliable when the clinical picture conflicts with the measured ferritin value [3]. Clinical interpretation of ferritin should account for potential biotin assay interference, particularly when supplements are taken at pharmacologic doses [2], [3].
When More Specific Evaluation Is Most Relevant
Further clarification is most relevant when ferritin results are discordant with symptoms and other iron studies, or when the ferritin assay platform is known to be susceptible to biotin-streptavidin interference [2], [3].
Summary Statement
Biotin supplementation has not shown a consistent direct effect on measured ferritin concentration in controlled trials [1]. However, biotin can cause assay interference that may lead to incorrect ferritin values on certain laboratory platforms [2], [3].