[Mucoviscidosis screening with immunoreactive trypsin. Initial experiences in Austria].

Area of Science:

• Biochemistry
• Genetics
• Pediatrics

Context:

• Newborn screening programs aim to detect genetic disorders early.
• Dried blood spot (DBS) analysis is a common method for neonatal screening.
• Early detection of cystic fibrosis (CF) is crucial for timely intervention and improved outcomes.

Purpose:

• To evaluate the efficacy of immunoreactive trypsin (IRT) testing on DBS for newborn screening of CF.
• To determine the incidence of CF in the southeast of Austria through IRT screening.
• To assess the reliability of IRT as a screening tool in the neonatal period.

Summary:

• Over 16,000 IRT measurements were performed on DBS, with over 15,500 in the first week of life.
• A provisional IRT cutoff of 750 ng/ml identified 0.86% of newborns for retesting.
• Four confirmed CF cases were identified through sweat testing after initial IRT elevations, with no false negatives reported.

Impact:

• IRT screening demonstrates reliability in identifying CF patients during the newborn period.
• Preliminary findings suggest a CF incidence of 1:3880 in southeast Austria.
• Further data collection is ongoing to establish comprehensive reference values for the first twelve weeks of life.