Neonatal Screening for Cystic Fibrosis by Dried Blood Spot Trypsin Assay.

Abstract

Newborn infants (47,127) from the Emilia-Romagna region [Italy] were screened for cystic fibrosis by dried blood spot trypsin assay. In the initial 12,099 subjects screened with a nonstandardized method, 2 children with cystic fibrosis [CF] were observed. Of the remaining 35,028 newborn infants, 299 showed high immunoreactive trypsin values; retesting revealed persistent elevation in 11. Sweat testing confirmed CF in 6 subjects and was normal in 5. Clinical monitoring of these 5 children has, as yet, shown no pathological signs. No false-negative test results have yet been identified. CF frequency would appear to be 1 case every 5890 newborn infants. Elevated immunoreactive trypsin is characteristic of newborn infants with CF and screening by determination of immunoreactive trypsin is of great benefit since it allows early diagnosis and a rational approach to therapy.