A few states have expanded the core screening panel to include clinically relevant non-sickling hemoglobin disorders, such as beta thalassemia and Hb H disease, but most states consider these as secondary screening targets and will refer newborns with a screening test showing a Hb F-only pattern or elevated Bart’s hemoglobin for definitive molecular testing [25]. Here, GSTM1 is linked to hemoglobinopathy.