Cystic fibrosis to worry or not?

Ok my son is 21 mos and I have noticed that I taste salt on his skin. Is this normal or should I worry?  I thought we all tasted a little salty but when I read about cystic fibrosis it made me worry.  Is it that they are excessively salty?  

My son passed the newborn screening and I had the carrier test and it was negative.  He is about 25% for weight and 39 % for height.  He started out at about 50% for weight and height but has been at steady growth on 25% since 10 mos old.  He does have issues with dairy so he doesnt get any so I always thought that was why is is on the smaller side.  He has never had an issue with being sick even have Influenza A with no complications.  His stools are on the softer side and can be watery but they are never fowel smelling.  If they are formed which lately they are they do sink.

Am I worry for no reason I just noticed the salt and now I am constantly checking to see if he tastes salty :(

[David S. Wilson, MD, FCCP]

My apologies, but this is an adult pulmonary physician and your question is best answered by a pediatric specialist

[DonnaMM]

CF is a genetic disease so both you and the father must carry the trait. If you tested negative there is no possible way he can have CF. if you are really concerned you can ask for another test to be sure you are not a carrier.

[threeandahalf]

I know this is a bit late, but the newborn screening only tests for about 56 of over 1500 known CF mutations, as does the carrier screening. We have had both. It is by all means possible her and her child carry one of the other 1450 mutations.