The intraerythrocytic multiplication factor (IMF) correlates strongly with erythrocyte indices. A, Linear regression analysis showing a strong positive correlation between mean IMFs for the P. falciparum 3D7 line and mean MCHCs of control and hemoglobinopathic erythrocytes. B, Linear regression analysis showing a positive correlation between mean IMFs for the P. falciparum 3D7 line and mean MCHs of control and hemoglobinopathic erythrocytes. C, Linear regression analysis showing a positive correlation between mean IMFs for the P. falciparum 3D7 line and mean MCVs of control and hemoglobinopathic erythrocytes. D, Linear regression analysis showing a strong correlation between mean IMFs for the P. falciparum 3D7 line and the number of functional α-globin genes in normal and α-thalassemia trait erythrocytes. Abbreviations: HbAS, hemoglobin A and S heterozygosity (individuals with sickle cell trait); HbSS, hemoglobin S homozygosity (individuals with sickle cell disease); MCH, mean corpuscular hemoglobin; MCHC, mean corpuscular hemoglobin concentration; MCV, mean corpuscular volume; thal, thalassemia.