Katie, this site has members from around the world, but yes, you'll see a lot of US terminology. Pulmonologist is respiratory consultant in the uk, I think. ER is A &E. I agree with liza (ratatosk) that pursuit of cf diagnosis with full genetic sequencing is less common in the uk. I get this impression from the uk site "bronchiectasis r us" where a number of people seem like they would have a cf diagnosis if they had more comprehensive testing.
You should check it out, especially if you are told your son doesnt have cf but CT scan shows bronchiectasis. Its a mostly uk message board for bronchiectasis-- a kind of lung damage caused by CF, immunodeficiency, cilia problems and more. I would still spend a lot of time here though because the quantity of useful information is very high. Moreover, treatments seem to start with the cf population, then get passed along to people with bronchiectasis later, but non cf docs aren't always aware of them and are used to dealing with a population in their 60s and 70s.
Best of luck.