Assessment of biotin interference with qualitative point-of-care hCG test devices.

Biotin is commonly used as a dietary supplement for the claimed benefits of promoting healthy hair and nail growth and is available without a prescription at doses up to 10mg/capsule. Biotin-mediated interference in immunoassay testing is an emerging issue for clinical laboratories and previous studies have indicated that biotin at regularly encountered doses may interfere with these assays. In this study, we evaluated the effect of supplemental biotin on seven POC urine hCG test devices using purified biotin and urine collected from four volunteers consuming 10mg biotin/day. Six of the seven devices showed no evidence of biotin interference as each device's control line remained clearly detectable at all biotin concentrations tested. However, the QuickVue device control line demonstrated a marked decrease in intensity when used to test solutions containing >5μg/mL biotin. The absence of a control line during patient testing has the potential to delay care due to the generation of an invalid test result and lead to additional unnecessary testing. It is not realistic to measure urinary biotin concentrations in every patient undergoing qualitative urine hCG testing but biotin supplementation should be considered if repeat testing on a patient sample generates an invalid test result.