CF?

My 6 year old son has the following symptoms, I'm wondering if it could be CF even though the sweat test results were negative for one arm and inconclusive on the other. Is it worth getting genetic testing?

1-Chronic cough;
2-Chronic sinusitis (sinus CT scan);
3-Lung inflammation and nodule in lung, right lower lobe (bronchoscopy);
4-Asthma;
5-Air-fluid level in right mastoid;
6-Frequent infections and antibiotic use, including 2 separate cases of pneumonia last year;
7-Allergic shiners, all allergy tests have come back negative;
8-Anemia;
9-Failure to thrive - his bmi is off the chart, however he really didn't start to drop until around 3;
10-Stomach pain with only occasional loose floating stool (he used to constantly have loose floating stools, however a few months ago he seemed to get much better);
11-Hand pruning. I had no idea this might be related to CF until I did a search, I just noticed how terrible they look when he gets out of the bath. They get really white and completely pruned, his palms and fingers have a strange texture that I do not know how to explain. His hands prune within a couple of minutes of being in water and by 5 minutes they look like what someone else's hands would look like after a day at the pool.
12-"Serum sickness" to penicillin. Recently discovered when he broke out in hives and his face swelled to the point that he couldn't open one eye and barely the other. He spent the night in the PICU with IV steroids. Allergy test for penicillin came back negative, restarted on Augmentin and once again within 10 days broke out in hives.
He's had 2 previous inguinal hernia repair surgeries. He is currently on Flovent, Albuterol, Singulair, Flonase and Claritin by doctor's orders.

Thanks for any input.