8yr old daughter geting a sweat test done

My 8yr old daughter has been sick since NOV, she has had rattling/weezing, congestion and a presistent non productive cough ( the times that she has expelled mucous it has been thick a dark green). Anyways we have been tossed around from doctor to doctor, first it was a common cold, then possiably something lodged in her throat (umm ok), then it was asthma, then may be allergies , then asthma again....she has hand MANY MANY antibiotics (the good ones), breathing treatments , steroids, otc meds, x-rays etc. ALL OF THEM DID NOT WORK! We are now seeing a pedi pulmonlogist (sp?) he did a breathing test which was impossianle to get a reading due to all the gunk in her chest, he did an chest x-ray (mild inflammation of lungs) then he did a culture & sensitvity test, in which he made the diagnosis that she has Presistent Bacterial Bronchitis (sp?), in which she was given the antibiotic that was supposed to be sensitve to  , well again failure...Now she is on ZYVOX whic she has been taken for 3 days and as of yet I do not see any improvement, he has also ordered her to get a sweat test which she has on May 3rd, depending on the results of the test and if this new antibiotic works she may have to get inevanious antibiotics. Besides congestion and cough she has no other symptoms, she is a good eater and it shows   and I did the lick test on her arm and she thought I was CRAZY!, but i did not taste salt....so is she someone who would seem like they might have CF? her doctor did tell me he does not think she has it but wants to rule it out. Any feedback is welcomed thanks ahead