Comparison of methodologies to detect hemoglobinopathy carriers in a multi-ethnic sperm donor population

An estimated 7% of the world's population are carriers for a hemoglobin disorder. Current guidelines recommend carrier screening by complete blood count, with follow-up hemoglobin electrophoresis or fractionation based on abnormal result or ethnicity. Advances in molecular genetic testing are thought to increase carrier detection. This study compares carrier screening methodologies in a multi-ethnic sperm donor population. A retrospective analysis was conducted using data from a US sperm bank. All men underwent carrier screening for hemoglobin disorders via complete blood count, hemoglobin fractionation, and molecular testing. Results were compared using counts and percentages. McNemar's exact test was used to examine differences in the marginal probabilities of screening methodologies. Of the 438 tested, 25 (5.7%) were identified as carriers of at least one hemoglobin disorder by molecular testing. Seventeen (68%) of those carriers were missed by recommended methods. No identified carriers were detected by recommended methods but missed by molecular testing. The difference between these discordant pairs was significant (p-value < 0.001). The majority (44%) of carriers were mixed ethnicity, followed by 36% White. Results indicate that molecular screening methodologies have a greater ability to detect carriers of hemoglobin disorders compared to currently recommended methods in a multi-ethnic population.