Newborn Screening Practices and Alpha-Thalassemia Detection — United States, 2016

摘要

Alpha-thalassemia comprises a group of inherited disorders in which alpha-hemoglobin chain production is reduced. Depending on the genotype, alpha-thalassemia results in moderate to profound anemia, hemolysis, growth delays, splenomegaly, and increased risk for thromboembolic events; certain patients might require chronic transfusions. Although alpha-thalassemia is not a core condition of the United States Recommended Uniform Screening Panel * for state newborn screening programs, methodologies used by some newborn screening programs to detect sickle cell disease, which is a core panel condition, also detect a quantitative marker of alpha-thalassemia, hemoglobin (Hb) Bart’s, an abnormal type of hemoglobin. The percentage of Hb Bart’s detected correlates with alpha-thalassemia severity. The Association of Public Health Laboratories’ Hemoglobinopathy Workgroup conducted a survey of state newborn screening programs’ alpha-thalassemia screening methodologies and reporting and follow-up practices. Survey findings indicated that 41 of 44 responding programs (93%) report some form of alpha-thalassemia results and 57% used a two-method screening protocol. However, the percentage of Hb Bart’s used for thalassemia classification, the types of alpha-thalassemia reported, and the recipients of this information varied widely. These survey findings highlight the opportunity for newborn screening programs to revisit their policies as they reevaluate their practices in light of the recently released guideline from the Clinical and Laboratory Standards Institute (CLSI) on Newborn Screening for Hemoglobinopathies ( 1 ). Although deferring to local programs for policies, the report used a cutoff of 25% Hb Bart’s in its decision tree, a value many programs do not use. Standardization of screening and reporting might lead to more timely diagnoses and health care services and improved outcomes for persons with a clinically significant alpha-thalassemia.