Single-centre prospective evaluation of the first 5 years of cystic fibrosis newborn screening in Germany

Abstract

BackgroundIn 2016 a nationwide Cystic Fibrosis Newborn-Screening (CFNS) was newly implemented in Germany, using an IRT/PAP/DNA screening algorithm that differs from most other nationwide screening programs.MethodsWe analysed real-life feasibility of the confirmation process with respect to our pre-specified procedural objectives. These included overall accuracy through false negative and positive results, effectiveness of the Bavarian tracking system, and accuracy of Macroduct or Nanoduct sweat conductivity compared to quantitative chloride determination. All consecutive CFNS-positive newborns assigned to our CF center and born between September 1, 2016, and August 31, 2021 (n=162) were included.ResultsThe German CFNS was feasible at our CF center as all procedural objectives were met. Positive predictive value (PPV) of positive CFNS was low (0.23) and two initially negatively screened children were later diagnosed with cystic fibrosis (CF). The tracking system was highly efficient with a 100% tracking rate. The Macroduct and Nanoduct systems had a comparable success rate (93.2%versus95.9%). Importantly, conductivityviaMacroduct was more accurate thanviaNanoduct (0 and 4 false positive newborns, respectively).ConclusionsCF confirmation diagnostics of neonates in a certified regional CF center was well managed in daily routine. Positive predictive value of the German CFNS needs to be improved,e.g.by extending the DNA analysis within the screening algorithm and by increasing the number of variants tested. The Bavarian tracking system can serve as a successful model for other tracking systems. We preferred the Macroduct system because of its more accurate sweat conductivity readings.