Typical flow cytometric analysis of (A) normal RBCs and (B) thalassemic RBCs (HbE/β-thal (splx), incubated without AV-FITC; (C) normal RBCs incubated with 1 mmol/L calcium in the presence of 4 μmol/L ionophore A23187 labeled with AV-FITC, and (D) thal RBCs (HbE/β-thal (splx) labeled with AV-FITC. RBCs were selected by their light scattering properties and the number of cells with fluorescence above background was defined by gate M1.