Cystic fibrosis and erroneous sweat tests.

Making the diagnosis of cystic fibrosis requires clinical suspicion and sweat tests. 
Physicians today are aware of the main clinical features of pulmonary 
and pancreatic involvement and are suspecting the diagnosis earlier than in 
past years. The accuracy of the sweat test is the most 
crucial factor in confirming the diagnosis. The present case illustrates this 
point. The main purpose of this paper is to serve as 
a reminder that the sweat test is often less than accurate 
as frequently performed. The principal pitfall of sweat testing at present 
seems to be the use of a chloride electrode applied to 
the skin without assurance that an adequate amount of sweat is 
present. 