Subject characteristics and summary data for subjects tested during assay development.

Groups were defined as follows: control; healthy volunteers with no known CF connection–one was negative for most common mutations via genotyping. Heterozygotes: parents or siblings of CF subjects; all confirmed via genotyping. The CFPI, CFPS and CFTR-R groupings were assigned by the CF clinic at Stanford based on clinical evaluations and genotyping. Number of tests indicates tests analyzed for the data shown in following 8 columns. Unavailable data indicated by “−”. Only adult subjects were tested. One CF subject was tested ∼1 year after a lung transplant. Ratios were averaged for each gland’s response to MCh and cocktail to give the mean β-cocktail/MCh (C/M) ratio. Either sums or means ± S.D. are shown for selected group measures.