Sara does not grow too well either, but after she started the tube feeding it's gone better. She has been off the tube now for 3-4 weeks, but still eats the "tubing milk" out of a bottle. The reflux is not that bad anymore either after the tube went...She does better on solid foods too, but not "quite there" yet.
You have to excuse my bad English skills, but I hope you all understand me.
I understand from the CF team here that the 4 week interval on the throat culture test is their norm.