Comparison of the newly formulated beckman access free T4 (Thyroxine) assay on the DXI 800 analyzer with the current Beckman free T4 (Thyroxine) assay for biotin Interference: New assay is free from biotin interference.

Background: Biotin causes significant positive interference with Free T4 (thyroxine) measurement using the current Beckman assay. Recently, Beckman reformulated the FT4 assay to overcome biotin interference. We compared the effect of biotin on both current and newly formulated FT4 assays.