Louis, Missouri (n = 236), and pregnant women at <20 weeks gestation from Cleveland, Ohio (n = 397), we compared subjects’ anemia status based on capillary Hb concentrations in finger puncture samples as measured by the HemoCue system with their anemia status based on venous Hb concentrations as measured by the HemoCue and Coulter Counter. The gene discussed is GSTM1; the disease is anemia (phenotype).