hey i'm robert and was dx with cf when i was 14. i was diagnosed with a sweat test and then they did a genetic test just to be sure and to find out what mutations i have, i have the delta 508 and another but i don't remember it right now. I know that not knowing for sure can really be nerve wrecking but hang in there, i would suggest that if insurance will pay for the sweat test and the genetic get both because the sweat test has a faster turn around time and you can get results sooner and the genetic test will tell you which mutations your son has if he has cf. if it turns out that he does have cf start learning what you can about it and keep asking questions, its the easiest way to get answers. keep us posted on how things turn out.