No evidence yet of any benefit

Neonatal screening for cystic fibrosis by using a simple test that can be performed on the “blood spots” routinely collected in screening for phenylketonuria and hypothyroidism raises exciting possibilities. The test is relatively easy to perform and the specimen is already collected, but even a simple test performed on millions of individuals will be costly, and the early knowledge of a serious disorder will cause more harm than good if there is no effective remedy. The results of a large randomised trial of neonatal screening for cystic fibrosis have recently been published in the New England Journal of Medicine.1 The trial involved two thirds of a million newborn infants and their subsequent follow up. The conclusion that screening and subsequent treatment improves the growth and development of children with cystic fibrosis was met with enthusiasm.2 Unfortunately the conclusion may not …