Where I am, I can't imagine a situation where anybody other than an experienced respirologist would order a bronch. I think the docs performing the procedure would also want to know why it is being ordered. They don't do these tests willy-nilly as some kind of fishing expedition.
In my case the docs did not know exactly what they were looking for but they had to get a better look inside my lungs. I had gone from being very healthy and active to being very sick (critical condition) in the course of a week and the nature of my inflammation was such that they could not get a really good diagnosis from the CT alone.
The procedure was done on Day 4 of a 55-day hospital stay.