CD19 and atrial fibrillation: By setting positive and negative gates for AF (Figure 3C) and re-calculating the compensation matrix with AF as a measurable parameter, AF spillover into other detectors was minimised, as shown with the correction of false signal using Fluorescence Minus One (FMO) (Figure 3D) and on CD45+ HLA-DR+ CD3- CD19- cells (Figure 3E).