Jessica, I just wanted to say you are being a good mommy by being on this site and learning more about cf and care for your child. After all how can you question the care or not question the care for that matter that your daughter is getting if you aren't informed. Although some of us might come off sort of strong, we're all here to learn and are happy that you're striving to be involved with Jae's care not just being a yes man. It's not fun putting yourself out on a limb to be attacked. It takes A LOT of work to care for a cfer and your understanding of why she needs you is so important. I hope you keep posting. No question is stupid. The more you read on here the more you'll see how much varies with cf. For example, the way you say all cfers cough up mucus. This isn't true. There are many adults on here that aren't productive. Does it mean they have mild cf? Not always. Some just aren't doing proper lung clearance, some are dehydrated and can't get the mucus out while others maybe don't have much mucus to get out. A change in mucus production amount is reason for concern if nothing has changed. The fact that Jae has started the Vest might very well be the reason for more mucus but the doctors don't want to see a productive cough at age 5 if it can be avoided. Not to say they don't want her to get the mucus out but rather they don't want there to be any mucus to come out. A sputum culture is a great next step after a mucus production increase is discovered because like others have said if there's no bug to treat then IVs aren't the thing to do. Maybe it is allergy related. You've got to give them credit for trying to get to the bottom of it.