I blew a positive breath test for SIBO before I had my colectomy. Treatment with Xifaxan didn't really do anything (it was more of a last ditch guess that perhaps resolving the SIBO would improve the UC flare, so I suspect even if it successfully treated the SIBO I wouldn't have noticed).
I think a breath test is easier than having a pouchoscopy, if you can find a place to administer it.