Challenges and opportunities in the implementation of the neonatal screening for cystic fibrosis

Abstract

INTRODUCTION: Early detection of cystic fibrosis (CF) by newborn screening (NBS) has a positive effect on the clinical outcome of the disease however, its implementation is complex and there is no universal protocol. The quantification of immunoreactive trypsinogen (IRT) is used as initial biomarker of all current CF-NBS algorithms. OBJECTIVE: To present the preliminary results of the application of an algorithm for the NBS of CF in the Ministry of Health of Mexico. MATERIALS AND METHODS: Retrospective study of the results of the application of an algorithm consisting of IRT/IRT quantification followed by sweat test (ST) for the detection of CF in the NBS program of the Ministry of Health of Mexico. RESULTS: Filter paper blood samples were obtained from 1,273,727 newborns (NB), being 1,267,122 specimens suitable for biochemical processing; 3,216 samples showed IRT blood values above 95.5 percentile. Second IRT sample was obtained only in 54% suspicious NB. 1,787 ST were performed and 202 highly CF suggestive cases (1:6,273 NB) were detected and sent to medical follow-up. The high number of extemporaneous samples contributes significantly to the high number of ST. Our results allow us to identify the main difficulties of the CF NBS implementation using the IRT/IRT/ST algorithm. CONCLUSION: The incorporation of this first NBS algorithm for CF detection in Mexico represents an achievement however, it is necessary to improve it.