Cystic fibrosis serum effect on the short circuit current of rat jejunum.

Sera from 100 subjects were tested for the presence of the cystic 
fibrosis (CF) "factor" utilizing the short circuit current rat jejunum bioassay. 
Comparing the mean percent decrease in short circuit current, the presumed 
normal group differs from the homozygous CF group at P = 
0.001 and from the heterozygous group at P = 0.05. The 
two CF genotypes are statistically different at P = 0.004. There 
is, however, a large overlap among the three groups, which limits 
the assay's utility as a guide for factor purification as well 
as clinical use. 