Assessing the improvements in the newborn screening strategy for cystic fibrosis in the Balearic Islands

• We assessed the newborn screening program in the Balearic Islands during the past 14 years.
• The incidence in the smaller islands (Minorca, Ibiza, Formentera) is about 5 times higher than in Majorca.
• Different changes in the protocol helped reduce the number of sweat tests performed without any false-negative rate increase.

ObjectivesNewborn screening strategies for cystic fibrosis (CF) are run worldwide, and aim at the early detection of the disorder to significantly improve the quality of life. Elevated levels of immunoreactive trypsinogen (IRT) represent a high likelihood for the screened child to be affected with CF. However, the specificity of IRT is low. The objective of this study was to assess the screening program in the Balearic Islands during the past 14 years.Design & methodsWe evaluated all results of the screening program after 14 years, by considering all changes in the protocol and assessing the number of positive samples, the mutations detected, the number of sweat tests performed, the incidence of CF and the presence of false-negative cases.ResultsDespite a great variability among the different Balearic Islands, the global incidence of CF was 1:6059 for the 14 years assessed. The incidence in the smaller islands is about 5 times higher than in Majorca (1:2376 versus 1:10,613). After different changes in the protocol, an IRT cut-off value of 60 ng/mL was established. The two most common mutations are ΔF508 and G542X, in accordance with other geographical regions.ConclusionsThe changes in the protocol helped reduce the number of sweat tests performed without any increase in the false-negative rate.