2.1.5 Data analysis
Estimated annual percentage change was used to evaluate the trend of PKU
screening and morbidity index. A t -test for two independent
samples was used to compare the differences of the neonatal disease
screening rate, recall review rate, and PKU morbidity between Shaanxi
Neonatal Disease Screening Center and the whole province. P< 0.05 was considered to indicate statistical significance.