Minimally invasive 13C-breath test to examine phenylalanine metabolism in children with phenylketonuria

Our study shows that the 13C-PBT can be a minimally invasive, safe and reliable measure to examine phenylalanine metabolism in children with phenylketonuria. The breath data are corroborated by blood phenylalanine levels in children who had increased responses in 13CO2 production, as reviewed post-hoc from clinical charts.