“…12 Since 2008, screening for SCID has been implemented in more than 40 states in the US, with several pilot studies performed in Europe and the UK. 9,10,[13][14][15][16] To date, more than 100 cases of SCID have been identified by NBS world-wide. 10,16 In all published studies, screening programmes measuring TREC have correctly identified infants with typical and atypical SCID, and there were no cases of SCID that were not detected by NBS and later identified.…”