Representative two-parameter dot plot of P falciparum–infected unbiotinylated red blood cells (RBCs) and biotinylated RBCs stained with biotin (x-axis) and hydroethidine (y-axis). (A) Unbiotinylated normal RBCs and biotinylated normal control RBCs; (B) unbiotinylated thalassemia RBCs and biotinylated normal control RBCs. Upper left quadrant shows unbiotinylated RBCs with stained parasite DNA, upper right quadrant shows double staining of both biotinylated RBCs and parasite DNA. Lower left quadrant represents noninfected unbiotinylated RBCs and lower right quadrant shows noninfected biotinylated RBCs. Percent parasitemia in unbiotinylated and biotinylated normal control RBCs are 17.3 and 17.9, respectively (A); percent parasitemia in unbiotinylated thalassemic RBCs and biotinylated normal control RBCs are 1 and 17.7, respectively (B).