Newborn screening (NBS) for cystic fibrosis (CF) not only identifies infants with a diagnosis of CF, but also those with an uncertain diagnosis of cystic fibrosis (CF), . CF transmembrane conductance regulator (CFTR)- related metabolic syndrome (CRMS) or CF screen positive inconclusive diagnosis (CFSPID). | Immunoreactive trypsinogen levels in newborn screened infants with an inconclusive diagnosis of cystic fibrosis