Newborn screening (NBS) for severe combined immunodeficiency (SCID) using T-cell receptor excision circles in dried blood spots has been implemented in the United States and many other regions and countries globally. The Clinical Immunology Society and the Association of Public Health Laboratories jointly formed the SCID Harmonization Initiative to facilitate comparison of NBS reporting practices to promote global consensus and collaboration.

To assess current NBS SCID practices using a global survey and to report the findings from the phase 1 component.

An 18-question survey was distributed to all known SCID screening programs worldwide. Only 1 response per region was analyzed. Examples of international screening algorithms were also solicited and included.

A total of 200 responses were received, of which 80 responses were unique and used for further analysis. Of the 39 non-US countries, 15 (38%) reported national universal screening and 24 (62%) reported regional, pilot, or other screening. Additional questions pertained to methodology and reporting, with particular emphasis on communication of the clinical urgency of an abnormal T-cell receptor excision circle result.

This global survey confirmed that the approach to NBS SCID varies widely, underscoring the need for harmonization at multiple steps, particularly for reporting and interpretation. This is the first study to capture global NBS SCID practices, and these findings provide the basis for creation of a phase 2 consensus reporting framework, which will be developed by the same SCID Harmonization Committee that created the current study.