The Decline of the Sweat Test: Comments on Pitfalls and Reliability

Eleven false positive and eight false negative sweat test results were found in a survey of 254 chest clinic patients thought to have cystic fibrosis. A larger and earlier study had given essentially no false results. Comments are made concerning the physiology of sweating, the pathophysiology of cystic fibrosis, and the application of Faraday's Law. Failure to appreciate these principles has led to inappropriate and dubious modifications of the sweat test pro cedure. A strong plea is made for the careful performance of a basically sound procedure which has such profound genetic and prognostic implications.