The report by Berry et al (see p 930) raises the question of mass screening of newborns for cystic fibrosis (CF). The authors suggest that mass screening is advisable, but do not believe enough data are available to recommend the best procedure. Both of these conclusions may be questioned. The advantages of early diagnosis should be examined. Also, since their article reports the examination of 65,000 meconium specimens, and a collaborative study1 funded by the National Cystic Fibrosis Foundation reports the examination of more than 100,000 specimens, it should be possible at this point to draw some conclusions about the efficacy of various testing procedures.
It is difficult to argue that the early diagnosis of any disease is not in some way beneficial. However, one may vastly overstate the benefit. This seems to have occurred when Berry et al quoted an estimate "that up to 90% of undiagnosed CF