Screening for cystic fibrosis by analysis of meconium for albumin and protease inhibitors.

A qualitative method of detecting elevated meconium protein concentration was compared with a method of determining meconium albumin concentration by electroimmunoassay since elevated meconium protein levels can indicate pancreatic insufficiency caused by cystic fibrosis. Between 5 and 10 per 1000 healthy infants passed meconium specimens that gave a false positive reaction with the Boehringer Mannheim test strip and contained a greater than expected concentration of albumin. It was possible to exclude pancreatic insufficiency in all of these children by determining the ratio, albumin : alpha1-antitrypsin in meconium and subsequent faecal specimens, since it was found that values of this ratio in excess of 2.0 suggested pancreatic insufficiency of the type associated with cystic fibrosis. Three of 14 neonates with subsequently proven cystic fibrosis yielded meconium specimens giving negative test strip results and low albumin concentrations. In two of these patients, the ratio, albumin : alpha1-antitrypsin in the meconium was within normal limits but, within two months of birth, the albumin : alpha1-antitrypsin ratio in the faeces of both children was greater than 3.0 suggesting that pancreatic insufficiency had developed.