Severe combined immunodeficiency (SCID) is a profound inborn error of immunity which is uniformly fatal if not diagnosed and treated within the first few weeks of life. Newborn screening (NBS) for SCID was introduced in New Zealand (NZ) in late 2017. To date, almost 500,000 babies have been screening in NZ the first few days after birth. Screening is based on the quantification of T-cell receptor excision circles (TREC), which are absent in babies who lack T-cells. Screening is sensitive to SCID, but babies with non-SCID T-cell lymphopenias can also be detected by screening.
Mark de Hora (Sun,) studied this question.