Unable to get a sweat test

For the past 1 and half years, my daughter(5 now) has been battling chronic cough, bouts with pneumonia, and now some reflux and constipation.  She has seen several specialists that feel she is clinically CF but we have tried to obtain a sweat chloride test on her 4 different times without getting enough sweat in the cylinder.  They did the genetic screen but it tests for only 32 of 1000 mutations and it was not positive.  Yet, all symptoms including her paleness and in ability to gain and maintain weight(she wighs 42 down from 45).  Recently she had atelectasis and pneumonia caused from what we think was adenovirus.  Has anyone here been diagnosed with a mutation different than the main 32 or trouble obtaining a sweat chloride.

Thanks for any information that you could give.

I do not know for sure but it is a local childrens hospital that do several on a regular basis.  What does the Ambry test show?