Comparison of the errors due to the use of gauze and the use of filter paper in the gravimetric chloride titration sweat test.

Potential sources of error in the Gibson and Cooke method of sweat 
testing using gauze and filter paper as collection media as described. 
The absolute chloride content of gauze was higher than that of 
filter paper; however, the variability of chloride contents between the two 
was insignificant. Complete chloride elution from filter paper requires more time 
than elution from gauze. A method of determining probability of a 
clinically acceptable measurement based on sweat sample size, chloride determination, and 
variability of chloride in collection media is also described. 