Camacho, BernardoPereira, LuísaBragança, RaquelCastanhinha, SusanaPenteado, RaquelSilva, Teresa ReisMiragaia, PedroSilva, SóniaCardoso, Ana L.Barbosa, TelmaFreitas, CristinaGonçalves, JuanMarcão, AnaVilarinho, LauraBarreto, CelesteConstant, Carolina2026-01-292026-01-292025-08-27Int J Neonatal Screen. 2025 Aug 27;11(3):69. doi: 10.3390/ijns11030069http://hdl.handle.net/10400.18/10786The implementation of newborn screening (NBS) has revolutionized the diagnostic landscape of cystic fibrosis (CF). In Portugal, NBS was initiated in October 2013 through a pilot study and was subsequently fully integrated into a nationwide program by December 2018. Infants with positive screening results are referred to a specialized CF reference center for diagnostic confirmation, employing Sweat Chloride Testing (SCT) and genetic testing for CFTR variants. We aimed to analyze infants with a positive CF screening and determine the false positive and false negative rates, as well as to calculate the positive predictive value and sensitivity of our NBS program. A retrospective nationwide analysis was conducted on infants with a positive NBS for CF between October 2013 and February 2023. Two hundred and forty infants were referred from the NBS program; 74 (30.8%) were confirmed to have CF through SCT and genetic testing. Sensitivity was 93.2%, and the positive predictive value (PPV) was 30.8%. In addition, 48.5% were homozygous for F508del variants, and 87.8% had at least one F508del variant. Guidelines set forth by the European Cystic Fibrosis Society advise NBS programs to achieve a minimum PPV of 30% and a minimum sensitivity of 95%. Our report demonstrated good compliance with these recommendations.engNewborn ScreeningCystic FibrosisDoenças GenéticasFibrose QuísticaRastreio NeonatalPortugaljournal article10.3390/ijns110300692409-515X40981300