Can bronchoprovocation tests only check for asthma?

Depends... Bronchorovocation tests actually test for bronchospasm which can be present in other diseases besides asthma. Other diseases include some sinus diseases, cystic fibrosis, copd, etc. So, if the test is positive for the presence of bronchospasm, your doctor still needs to consider the whole clinical picture to make the correct diagnosis.
Yes. As far as i know it checks for hyper reactivity of the airways. This is a hallmark of asthma.

Related Questions

Can bronchoprovocation tests only check for asthma?

No . Bronchoprovocation test like a methacholine challenge or mannitol challenge check for bronchial hyper reactivity. However there are only a few diseases that would cause a positive test -- e.g. Asthma, cystic fibrosis, congestive heart failure, allergic rhinitis. Interpreted in the right clinical setting one's doc can figure out the correct diagnosis. Read more...