Nathalie,
I am a fan of testing and really encourage patients to do so. However, despite that sometimes people cannot or won’t do them. I don’t think performing a breath test on everyone is warranted before probiotics unless you have a practice that specialized in SIBO. A suspicion of SIBO based on clinical symptoms is fairly straightforward so the test would be done to confirm that suspicion. If you think about the bulk of patients you see and have experience with in the past they mostly do fine with probiotics and prebiotics. Another way to look at it is giving these items to an individual where it causes problems should be an indication to them to do a SIBO breath test.
Sincerely,
Dr. Woeller