Quality of sweat test performance in the diagnosis of cystic fibrosis.

The sweat test, correctly performed, appears to be reliable, but results were 
found to be unreliable about half the time in 84 small 
community hospitals assessed. The reasons are inexperienced and untrained technicians, the 
infrequency of test performance, the use of unstandardized equipment, and the 
lack of appropriate standards. It behooves all clinical laboratory directors to 
re-examine and standardize their procedures and use the recommendations of the 
Cystic Fibrosis Foundation. Physicians should be made aware of the current 
situation and send their patients only to laboratories that perform the 
test reliably. 