Clinical Utility of Confirmatory Genetic Testing to Differentiate Sickle Cell Trait from Sickle-β+-Thalassemia by Newborn Screening.

Hemoglobin separation techniques are the most commonly used laboratory methods in newborn screening and confirmatory testing programs for hemoglobinopathies. However, such protein-based testing cannot accurately detect several hemoglobinopathies in newborns, especially when β-thalassemia mutations are involved. Here, we describe a consecutive cohort of newborns who were identified by newborn screening to have a likely diagnosis of sickle-β+-thalassemia (having an "FSA" pattern) who were determined to have sickle cell traits by confirmatory and genetic testing. We illustrate the clinical utility of genetic testing to make a correct and timely diagnosis in the setting of newborn screening for hemoglobinopathies.