Newborn Screening for Sickle Cell Disease in Sub-Saharan Africa: Initial Results of the ASH Consortium on Newborn Screening in Africa (CONSA) Program

Introduction: In 2018, the American Society of Hematology (ASH) established the Consortium on Newborn Screening in Africa (CONSA) for sickle cell disease (SCD), a program designed to implement standardized hemoglobinopathy newborn screening (NBS) coupled with early clinical management for children with SCD across sub-Saharan Africa. After a rigorous application and evaluation process, seven countries with large clinical catchment areas in sub-Saharan Africa were included into CONSA. We now present the initial cumulative diagnostic screening results, which represent the feasibility, training, and proof-of-principle stages of the consortium.

Methods: ASH members and staff work directly with national coordinators and local laboratory scientists to implement NBS using standardized isoelectric focusing (IEF) techniques. Blood samples are collected by heel prick in newborns and young infants at local hospitals and clinics; dried blood spots (DBS) are prepared and then transported to a central laboratory for testing. The laboratory techniques for conducting and scoring the IEF gels follow a Standard Operating Procedure (SOP) developed by CONSA and include known controls for hemoglobin A, F, S, and C. All DBS samples that are scored as SCD (hemoglobin FS or FSC) are initially repeated to verify the abnormal result; a subsequent new sample is then collected at the first clinical visit to confirm the diagnosis of SCD.

Results: To date, ten screening centers have been established in seven countries across sub-Saharan Africa: Ghana, Kenya, Liberia, Nigeria, Tanzania, Uganda, and Zambia. As of April 2024, a total of 73,903 unique DBS samples have been tested and scored with satisfactory results, which have been curated and uploaded to the ASH CONSA database. Sickle cell trait has been identified in 11,281 (15.43%) of DBS tested, ranging from a low value of 5.7% in Monrovia, Liberia to a high value of 23.7% in Kaduna, Nigeria. Sickle cell anemia has been identified in 1055 (1.44%) of DBS tested, ranging from a low value of 0.4% in Monrovia, Liberia to 2.8% in Jinja and Lira, Uganda. Hemoglobin variants have been recorded in 412 (0.56%) DBS samples with the vast majority of these found in Uganda and Kenya. Of the SCD cases identified, a total of 392 have been confirmed with an additional blood sample and the mothers and caregivers have been counselled. Efforts are ongoing to locate and enroll these infants into clinical management. Upcoming steps to increase the efficiency of SCD diagnosis include using point-of-care devices for disease confirmation, after a positive IEF result from the initial DBS sample.

Conclusion: The ASH-initiated CONSA program has demonstrated, and will continue to demonstrate, that NBS is feasible to conduct in high-burden low-resource areas within multiple countries across sub-Saharan Africa. The process of rigorous and repeated laboratory and technical training, coupled with a high-quality standardized SOP, has documented the high burden of sickle cell trait and disease across this region. Ongoing efforts to link children diagnosed with SCD with early clinical care will continue. Communication of these results with local, national, and donor partners will help raise awareness and should increase efforts toward universal NBS screening.