FlowCal

Flow cytometry is a widely used technique for measuring gene expression and other biological processes at the single-cell level. However, flow cytometry data is typically reported in arbitrary units, limiting its interpretation and comparability between experiments. The software tool, FlowCal, provides a convenient, non-proprietary solution for converting arbitrary units to molecules of equivalent fluorophore (MEF), the calibrated unit for flow cytometry data. FlowCal accepts Flow Cytometry Standard (FCS) files, is compatible with different calibration particles, and automatically gates data, calculates statistics, and produces publication-quality plots. The tool has been validated for E. coli and S. cerevisiae expression data and can reduce day-to-day variability due to instrument drift. FlowCal is available as an Excel interface or customizable Python scripts and can facilitate the adoption of standard fluorescence units in synthetic biology and beyond.