Pairing parents and offspring's HemoTypeSC Test to validate results and confirm sickle cell pedigree: a case study in Kisangani, the Democratic Republic of the Congo

Objectives: HemoTypeSC (TM) is one of the immunoassay methods currently used for the early diagnosis of Sickle Cell Disease (SCD) in newborns. Earlier diagnosis remains the key strategy for early preventive care needs and parents' education about the child's future well-being throughout his life. Before considering these children as sick and aligning them for regular medical monitoring, it may be valuable to confirm the HemoTypeSC result with a secondary laboratory testing method. In resource-limited settings, where confirmatory methods are not always available, we propose testing the parents to validate the HemoTypeSC result. Methods: This study explored this approach in the city of Kisangani. It was a prospective diagnostic accuracy study using genotype biological parents to evaluate HemoTypeSC's performance in the newborn. Results: Fifty-eight children born to 46 known mothers, and 37 known fathers, have been tested. The phenotyping showed that 41 (70.7%) children were SS, whose 37 were born to a couple AS/AS and 4 to a couple AS/xx. Of the 41 SS children, 8 (19.5%) were newborns and 33 (80.4%) were children; 12 (20.6%) children were AS, one of whom was born to a couple SS/AA and 11 to a couple AA/SS; 5 (8.6%) children were AA. In this population, the probability of offspring born to AS/AS parents being SS rather than AS is high (odds, 1.25). No statistical difference was observed between girls and boys. The pedigree of all 58 children has been confirmed. Conclusion: We demonstrated that testing biological parents with HemoTypeSC is a reliable confirmatory method for newborn screening but it presents some limitations discussed in the present article.