So my girlfriend's little brother has been diagnosed with cf... but the thing is he is just a half brother. She herself has never been tested and never in her life has had any sort of real respritory infection... she is in excellent shape and looks great in fact being a model. She is 17, but last year she was coughing up blood for a period of a few months and went to the hospital for tubulercolosis which tested negative. It stopped for a while and started again a few months ago with coughing up a little bit of blood maybe twice a week sometimes less. She has had a chronic cough her whole life but its generally mild and sometimes can go for days without having it. Also in the past she's had a couple times she simply quit breathing and could not take a breath one lasting over a minute. Besides this though shes full of energy ect... is there any possibility she might not have cf and if she does is this very severe? She was diagnosed with athma when younger. Thanks