{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,28]],"date-time":"2026-10-28T00:49:01Z","timestamp":1793148541215,"version":"4.5.0"},"reference-count":26,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2026,7,7]],"date-time":"2026-07-07T00:00:00Z","timestamp":1783382400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"the Committee of Science of the Ministry of Science and Higher Education of the Republic of Kazakhstan","award":["BR24992814"],"award-info":[{"award-number":["BR24992814"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJNS"],"abstract":"<jats:p>The early detection of Severe Combined Immunodeficiency (SCID) and X-linked agammaglobulinemia (XLA) prevents fatal outcomes. This study presents the first pilot TREC\/KREC newborn screening (NBS) program in southern Kazakhstan, a high-birth-rate region, to establish local reference ranges and assess operational viability. A multiplex real-time PCR assay was used to quantify T-cell (TREC) and kappa-deleting recombination excision circles (KRECs) from dried blood spots of 5000 unselected neonates. Biomarkers were normalized to copies per 106 cells using albumin as a diploid reference gene. Regional 0.5th percentile cut-offs were established (TREC &lt; 3165 copies\/106\u00a0cells and KREC &lt; 2554 copies\/106\u00a0 cells), and gender and gestational age did not significantly impact biomarker levels. While a low birth weight (\u22642500 g) significantly reduced KREC levels, the extreme lower distribution tails remained unaffected, validating the use of universal, unstratified thresholds. Applying these cut-offs yielded an optimal 1.0% initial recall rate. Consistent with global incidence rates, no true positive cases were identified. The established assay and universal percentile cut-offs demonstrate high levels of analytical reliability and demographic stability. This pilot confirms the regional pediatric healthcare infrastructure\u2019s readiness for a routine, population-based NBS program without the need for complex algorithms.<\/jats:p>","DOI":"10.3390\/ijns12030051","type":"journal-article","created":{"date-parts":[[2026,7,8]],"date-time":"2026-07-08T17:27:31Z","timestamp":1783531651000},"page":"51","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Implementation of TREC\/KREC Newborn Screening in a High-Birth-Rate Population: A Pilot Study of 5000 Neonates in South Kazakhstan"],"prefix":"10.3390","volume":"12","author":[{"given":"Gulzada","family":"Abdushukurova","sequence":"first","affiliation":[{"name":"Department of Therapy, Khoja Akhmet Yassawi International Kazakh-Turkish University, Shymkent Institute of Postgraduate Studies, Shymkent 160021, Kazakhstan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0007-2228-1260","authenticated-orcid":false,"given":"Alken","family":"Auyelova","sequence":"additional","affiliation":[{"name":"\u201cSan-Med Service\u201d Allergy Center, Shymkent 160000, Kazakhstan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Banu","family":"Kadyrbayeva","sequence":"additional","affiliation":[{"name":"Department of Therapy, Khoja Akhmet Yassawi International Kazakh-Turkish University, Shymkent Institute of Postgraduate Studies, Shymkent 160021, Kazakhstan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1277-4292","authenticated-orcid":false,"given":"Ardak","family":"Ayazbekov","sequence":"additional","affiliation":[{"name":"Faculty of Medicine, Khoja Akhmet Yassawi International Kazakh-Turkish University, Turkestan 161200, Kazakhstan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Dina","family":"Mussayeva","sequence":"additional","affiliation":[{"name":"\u201cSan-Med Service\u201d Allergy Center, Shymkent 160000, Kazakhstan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5655-5465","authenticated-orcid":false,"given":"Ainash","family":"Oshibayeva","sequence":"additional","affiliation":[{"name":"Faculty of Medicine, Khoja Akhmet Yassawi International Kazakh-Turkish University, Turkestan 161200, Kazakhstan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kumissay","family":"Babayeva","sequence":"additional","affiliation":[{"name":"Department of Special Clinic Subjects, Khoja Akhmet Yassawi International Kazakh-Turkish University, Turkestan 161200, Kazakhstan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Liliya","family":"Khairullina","sequence":"additional","affiliation":[{"name":"\u201cSan-Med Service\u201d Allergy Center, Shymkent 160000, Kazakhstan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9120-8565","authenticated-orcid":false,"given":"Karlygash","family":"Sadykova","sequence":"additional","affiliation":[{"name":"Department of Special Clinic Subjects, Khoja Akhmet Yassawi International Kazakh-Turkish University, Turkestan 161200, Kazakhstan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Gulnaz","family":"Nuskabaeva","sequence":"additional","affiliation":[{"name":"Department of Special Clinic Subjects, Khoja Akhmet Yassawi International Kazakh-Turkish University, Turkestan 161200, Kazakhstan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,7,7]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"14","DOI":"10.1111\/jpc.13659","article-title":"Newborn screening for severe combined immunodeficiency: Evaluation of a commercial T-cell receptor excision circle-based method in Victorian dried blood spots","volume":"54","author":"Richards","year":"2018","journal-title":"J. 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