{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,15]],"date-time":"2026-10-15T03:37:18Z","timestamp":1792035438864,"version":"4.4.0"},"reference-count":44,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2021,8,25]],"date-time":"2021-08-25T00:00:00Z","timestamp":1629849600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJNS"],"abstract":"<jats:p>Screening for severe combined immunodeficiency (SCID) was introduced into the Swedish newborn screening program in August 2019 and here we report the results of the first year. T cell receptor excision circles (TRECs), kappa-deleting element excision circles (KRECs), and actin beta (ACTB) levels were quantitated by multiplex qPCR from dried blood spots (DBS) of 115,786 newborns and children up to two years of age, as an approximation of the number of recently formed T and B cells and sample quality, respectively. Based on low TREC levels, 73 children were referred for clinical assessment which led to the diagnosis of T cell lymphopenia in 21 children. Of these, three were diagnosed with SCID. The screening performance for SCID as the outcome was sensitivity 100%, specificity 99.94%, positive predictive value (PPV) 4.11%, and negative predictive value (NPV) 100%. For the outcome T cell lymphopenia, PPV was 28.77%, and specificity was 99.95%. Based on the first year of screening, the incidence of SCID in the Swedish population was estimated to be 1:38,500 newborns.<\/jats:p>","DOI":"10.3390\/ijns7030059","type":"journal-article","created":{"date-parts":[[2021,8,25]],"date-time":"2021-08-25T23:25:50Z","timestamp":1629933950000},"page":"59","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":31,"title":["First Year of TREC-Based National SCID Screening in Sweden"],"prefix":"10.3390","volume":"7","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4495-1476","authenticated-orcid":false,"given":"Christina","family":"G\u00f6ngrich","sequence":"first","affiliation":[{"name":"Centre for Inherited Metabolic Diseases, Karolinska University Hospital, 17176 Stockholm, Sweden"},{"name":"Department of Molecular Medicine and Surgery, Karolinska Institutet, 17176 Stockholm, Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4506-9955","authenticated-orcid":false,"given":"Olov","family":"Ekwall","sequence":"additional","affiliation":[{"name":"Department of Pediatrics, Institute of Clinical Sciences, The Sahlgrenska Academy at University of Gothenburg, 40530 Gothenburg, Sweden"},{"name":"Department of Rheumatology and Inflammation Research, The Sahlgrenska Academy at University of Gothenburg, 40530 Gothenburg, Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9871-0961","authenticated-orcid":false,"given":"Mikael","family":"Sundin","sequence":"additional","affiliation":[{"name":"Department of Clinical Science, Intervention and Technology, Karolinska Institutet, 17177 Stockholm, Sweden"},{"name":"Section of Pediatric Hematology, Immunology and HCT, Astrid Lindgren Children\u2019s Hospital, Karolinska University Hospital, 14186 Stockholm, Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nicholas","family":"Brodszki","sequence":"additional","affiliation":[{"name":"Department of Pediatric Immunology, Children\u2019s Hospital, Lund University Hospital, 22242 Lund, Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0033-740X","authenticated-orcid":false,"given":"Anders","family":"Fasth","sequence":"additional","affiliation":[{"name":"Department of Pediatrics, Institute of Clinical Sciences, The Sahlgrenska Academy at University of Gothenburg, 40530 Gothenburg, Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Per","family":"Marits","sequence":"additional","affiliation":[{"name":"Department of Clinical Science, Intervention and Technology, Karolinska Institutet, 17177 Stockholm, Sweden"},{"name":"Department of Clinical Immunology and Transfusion Medicine, Karolinska University Hospital, 14186 Stockholm, Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sam","family":"Dysting","sequence":"additional","affiliation":[{"name":"Centre for Inherited Metabolic Diseases, Karolinska University Hospital, 17176 Stockholm, Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Susanne","family":"Jonsson","sequence":"additional","affiliation":[{"name":"Centre for Inherited Metabolic Diseases, Karolinska University Hospital, 17176 Stockholm, Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7598-9330","authenticated-orcid":false,"given":"Michela","family":"Barbaro","sequence":"additional","affiliation":[{"name":"Centre for Inherited Metabolic Diseases, Karolinska University Hospital, 17176 Stockholm, Sweden"},{"name":"Department of Molecular Medicine and Surgery, Karolinska Institutet, 17176 Stockholm, Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anna","family":"Wedell","sequence":"additional","affiliation":[{"name":"Centre for Inherited Metabolic Diseases, Karolinska University Hospital, 17176 Stockholm, Sweden"},{"name":"Department of Molecular Medicine and Surgery, Karolinska Institutet, 17176 Stockholm, Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4137-970X","authenticated-orcid":false,"given":"Ulrika","family":"von D\u00f6beln","sequence":"additional","affiliation":[{"name":"Centre for Inherited Metabolic Diseases, Karolinska University Hospital, 17176 Stockholm, Sweden"},{"name":"Department of Medical Biochemistry and Biophysics, Division of Molecular Metabolism, Karolinska Institutet, 17177 Stockholm, Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3016-0019","authenticated-orcid":false,"given":"Rolf 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