Presumptive Tests for Cystic Fibrosis Based on Serum Protein in Meconium

The meconium obtained from siblings of patients with cystic fibrosis was studied for its protein content to determine whether this procedure could be used as a marker of the disease in the newborn. Over a 9-year period 196 specimens were studied. Forty-nine of the 196 infant siblings developed cystic fibrosis and only 4 of this group gave a negative protein reaction. In the remaining group of 147, the protein test was positive in 46, but in a lesser amount. Two methods of testing were employed—a trichloracetic acid ring test and a slide agglutination test using antihuman albumin. Random control samples from 1,600 full-term babies yielded negative tests. This presumptive test is suggested as a possible screening method for the detection of cystic fibrosis with a reliability of approximately 90%. The measurement of sweat electrolytes, although difficult and time consuming in the newborn period, appears to be the most reliable technique of detecting cystic fibrosis.