GSTM1 and anemia (phenotype): Based on these results and reconsideration of the potential clinical utility of this test in the real world (outside of a research study) as a screening test for severe and profound anemia (Hb ≤ 7 g/dL and Hb ≤ 5 g/dL, respectively), the AnemoCheck assay was further optimized to more accurately detect these critical hemoglobin thresholds.