We read with great interest the letter from E. Sapey and co-workers on “The validation of assays used to measure biomarkers in exhaled breath condensate”. Indeed, we agree with E. Sapey and co-workers that the variability of current assays can be further improved.
However, in our opinion, this does not imply that “exhaled breathe condensate is not an ideal collection method for protein measurements”. One should be aware of the associated ambiguity. There are in fact two relatively separate methods that are involved in the technique of exhaled breath condensate. The first is the method used to collect the condensate of …