The cost-benefit of newborn screening for X-linked agammaglobulinemia and related B-cell lymphopenia.

Early detection of X-linked agammaglobulinemia (XLA) and other profound B cell lymphopenias (BCL) in newborns is crucial for timely intervention and improved clinical outcomes. The kappa light chain rearrangement excision circles (KREC) assay has emerged as an effective specific and sensitive tool for newborn screening (NBS) of XLA and other BCL. Large-scale studies have demonstrated that KREC-based NBS identifies affected infants before symptom onset, enabling prompt initiation of immunoglobulin replacement therapy (IGRT) and prophylactic antibiotics, thereby preventing recurrent infections, chronic organ damage, and reducing healthcare burden. Here, we evaluate the possible cost-benefit of NBS for XLA and other BCL. Economic evaluation shows that adding KREC screening to existing NBS programs is likely to be cost-effective and fulfills established criteria for NBS inclusion, supporting its adoption in universal NBS protocols.