Meconium screening for cystic fibrosis. An eight-year follow-up study

The results of more than eight years of screening for cystic fibrosis (CF), utilizing the albumin concentration in meconium, are reported. Over 28 000 meconium samples were tested, over 24 000 of them by the Boehringer-Mannheim strip test, and all samples considered as showing a trace or positive result were followed up by an immunological technique. Eight-three meconium samples contained more than 20 g albumin/kg dry weight meconium and five of these were from children who were found to have CF. One child with CF was missed in the screening. From these figures the sensitivity of the method for detecting CF children at birth was calculated to be 75%, the specificity 99.7%, the negative predictive value 100%, the positive predictive value 4.0% and the incidence of CF in Sweden about 1:4,500. The incidence of pathologically elevated meconium albumin concentrations was found to be 25 times higher in premature than in full-term infants. Since the number of false positive results creates a problem, we suggest that premature children (birth weight less than 2500 g) and newborns with melaena should be excluded from further follow-up studies.