Electrolyte values of sweat obtained by local and whole body collection methods in cystic fibrosis patients.

The composition of sweat and its relationship to the condition and site 
of collection are of interest in environmental physiology, dermatology, and the 
study of cystic fibrosis. This study was undertaken to compare the 
concentrations of sodium and chloride in whole body sweat of normal 
control patients and of CF patients obtained by thermal stimulation with 
samples collected locally by pilocarpine iontophoresis. Electrolyte concentrations in whole body 
sweat samples correlated in a highly significant fashion with sodium and 
chloride values found in arm patch sweat. Patients with CF, however, 
showed significantly higher sodium and chloride concentrations in arm patch sweat 
and whole body sweat, and increased sodium excretion rates. 