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SELECTBIO Conferences Circulating Biomarkers and Extracellular Vesicles Europe 2023


Global Inter-Laboratory Comparison Study to Standardize Measurements of Extracellular Vesicle Concentrations

Edwin van der Pol, Assistant Professor, Amsterdam University Medical Centers

Introduction: Concentrations of extracellular vesicles (EVs) in body fluids are upcoming biomarker for health and disease. The concentration of cell-type specific EVs can be measured with state-of-the-art flow cytometers. However, flow cytometers have different detection limits and therefore measure different EV concentrations in the same sample. Consequently, clinical research studies reporting EV concentrations lack reproducibility and are typically single-center studies, which precludes future clinical implementation. To overcome these problems, the European Union invested 1.8 million euro into the “METVES II” consortium, which aimed for developing reference materials and methods to calibrate flow cytometers. The developed infrastructure was tested in a global inter-laboratory comparison study including 39 flow cytometers from 24 laboratories.

Methods: Concentrations of platelet-derived (CD61-APC) and erythrocyte-derived (CD235a-PE) EVs were measured in stabilized and pre-labeled human plasma EV test samples. The flow rates were calibrated using metrologically traceable silica beads, fluorescence intensities were calibrated using beads with a known number of fluorescent molecules, and light scattering intensities were calibrated using polystyrene beads and Mie theory. EV concentrations were compared between flow cytometers within calibrated fluorescence and size ranges.

Results: Preliminary results from 25 flow cytometers show that calibration leads to reproducible EV concentrations. For the platelet EV concentration, the coefficient of variation of measured EV concentrations decreased from 75% without calibration to 25% after calibration.

Conclusions: This is the first inter-laboratory comparison study demonstrating that full flow cytometer calibration improves the comparability of EV concentration measurements between flow cytometers, thereby paving the road to multi-center clinical research studies on EVs.

Add to Calendar ▼2023-06-19 00:00:002023-06-20 00:00:00Europe/LondonCirculating Biomarkers and Extracellular Vesicles Europe 2023Circulating Biomarkers and Extracellular Vesicles Europe 2023 in Rotterdam, The NetherlandsRotterdam, The