2.1.1 Research material
Data of newborn PKU screening in Shaanxi province, China, were acquired
from the “National
Newborn Disease Screening Information Direct Reporting System,” and
data were taken from 11 newborn disease screening reports in Shaanxi
province from 2010 to 2018. Mutations in the PAH gene were present in 84
cases of PKU diagnosed by Shaanxi Neonatal Screening Center from 2010 to
2018.
2.1.2 Sample collection According to the requirements of the
“Technical Specifications for Blood Collection for Neonatal Disease
Screening” issued by the Chinese Ministry of Health (6), blood was
collected between 72 h after birth and the first full breast feeding.
Peripheral blood 0.5 ml was collected from the inner (or outer) edge of
the heel of the newborn. The first drop of blood was discarded and
another drop was applied to osmotic filter paper
(903™) for neonatal disease screening (diameter of the
blood spot on both sides of the paper ≥8 mm). The filters were then
air-dried, placed in a sealed bag, and stored at −80°C.