Proceedings: Experience with an ion-specific electrode to measure sweat chloride.

The Orion skin chloride measuring system had been evaluated in children of 
various ages. The method was found to give reproducible results in 
nearly all cases. Failure to obtain reproducibility was related to inadequate 
sweating by the subject and this was most likely to occur 
in the first week of life. There was generally a clear 
distinction between healthy children and patients with cystic fibrosis. The method 
was simple and reliable provided that the operator had had reasonable 
experience with the instrument. One distinct advantage of the method compared 
with the use of filter paper was the speed with which 
results were obtained. The design of the instrument made the method 
completely safe and only a few patients noticed slight tingling during 
iontophoresis. The mean sweat chloride in the 'normals' was 26.9 mEq/l., 
compared with 102.3 mEq/l. in the patients with cystic fibrosis. 