Biotin and high-sensitivity cardiac troponin T assay

INTRODUCTION: The high-sensitivity cardiac troponin T assay of Roche Diagnostics is known to have interference with high concentrations of biotin as this assay uses biotin-streptavidin binding as detection method. As studies so far have not shown if different biotin concentrations could have diverse influence on various troponin concentrations and whether interference could be removed by available protocol within corresponding turnaround time we aimed to investigate it. MATERIALS AND METHODS: Plasma samples were spiked with different concentration of biotin solution. Troponin T concentrations were tested on a Roche Cobas® 8000 module 602 analyser. Final concentrations of biotin and troponin T were 50, 100, 500 and 1000 μg/L and 18, 59, 201 and 6423 ng/L, respectively. Impact of different incubation times following biotin neutralization protocol described by Piketty et al. was also tested. RESULTS: We observed a mean of negative biases of 24, 56, 97, and 98% of the troponin T expected value at biotin concentrations of 50, 100, 500, 1000 μg/L. Neutralization protocol was applied on the sample with initial concentration of TnT of 59 ng/L at a biotin concentration of 1000 μg/L. Same results across different incubation times from 60 to 0 minutes were obtained (mean value 56.8 ng/L, coefficient of variation of 1.31%). We demonstrated that neutralization process had a dilution effect of the troponin concentration (loss of 4.5% to 9.6% of initial troponin value). CONCLUSIONS: Biotin interference is not dependent of initial troponin value. Interference could be successfully neutralized within a time frame compatible with emergency but results still should be carefully interpreted due to possible dilution effect.