Screening in Vein: Hemoglobin Electrophoresis Misses Most Alpha Thalassemia Carriers [A243]

INTRODUCTION: Carrier screening for alpha thalassemia is universally recommended in the U.S., regardless of a patient’s ancestry. While hemoglobin electrophoresis is traditionally recommended as the first-line test for alpha thalassemia carrier screening, newer genetic testing technology shows promise to improve the detection of alpha thalassemia carriers. METHODS: A retrospective chart review was conducted of 515 participants who received both hemoglobin electrophoresis and genetic testing for alpha thalassemia carrier screening at a U.S. commercial laboratory between March 2019 and October 2020. RESULTS: In this panethnic U.S. population, 8% of participants (42/515) were identified to be carriers of alpha thalassemia via genetic testing, and hemoglobin electrophoresis was abnormal for 12% (5/42) and normal for 88% (37/42). Among the 38 “silent” alpha thalassemia carriers identified via genetic testing, 13% (5/38) had an abnormal hemoglobin electrophoresis and 87% (33/38) had a normal hemoglobin electrophoresis. Among the four alpha thalassemia “trait” carriers identified via genetic testing, 0% (0/4) had an abnormal hemoglobin electrophoresis and 100% (4/4) had a normal hemoglobin electrophoresis. CONCLUSION: Hemoglobin electrophoresis is an older screening technology that failed to detect the majority (88%) of alpha thalassemia carriers identified by genetic testing in our study. Previous studies also found that genetic testing outperforms hemoglobin electrophoresis in alpha thalassemia carrier detection. Genetic testing should be considered as a first-line screening option for alpha thalassemia carrier detection to help providers identify more at-risk couples.