Cystic fibrosis newborn screening does not delay the identification of cystic fibrosis in children with negative results

Abstract

Background: Several studies have demonstrated the benefit of Cystic Fibrosis Newborn Screening (CFNBS) for early diagnosis and, hence, intervention but the impact of CFNBS on those children not detected on CFNBS is not known. CFNBS may provide false reassurance that all CF has been detected and, therefore, lead to a delay in the diagnosis of children with CF which is not detected on CFNBS. The aim of this study was to determine the impact of CFNBS on the presenting features of children with CF where CF was not detected on CFNBS.

Methods: Subjects at the CFNBS center were selected if CF was identified subsequent to a negative CFNBS with subjects at the No CFNBS selected based on the absence of ΔF508 mutations. Children presenting with features that would lead to investigation for CF independent of clinical status were excluded. Presenting features at diagnosis and pulmonary function at 6 years of age were extracted from medical records.

Results: Twelve children from the CFNBS site and 19 from the No CFNBS site were included in the analysis. The only significant difference between the two in features at diagnosis was lower mean weight z-scores at the No CFNBS site (-2.9 ± 1.8) compared to the CFNBS center (-1.4 ± 1.3, p<0.05). Age at diagnosis, presenting complaint and nutritional status did not differ by site. Growth parameters and pulmonary function at 6years of age showed no differences between sites.

Conclusions: This study demonstrates that access to CFNBS does not result in delay in diagnosis or poorer outcomes in those children for whom CF was not detected on CFNBS. In addition, children with CF not detected on CFNBS present with typical features of CF and sweat chloride results that are diagnostic of CF.