I've heard of some sort of hydrogen breath test being used for SIBO. I was treated with Rifamaxan (Xifaxan) and although I'm undiagnosed, whatever it is I have has been relatively quiet since I finished my 2nd round in January. It's nothing like it was, and while I would have months of no symptoms prior to treatment, I've never been this long with so few acute episodes. I think I really only had one in May. My GI couldn't find evidence of IBD, but said that sometimes IBS-type symptoms are caused by SIBO. He didn't bother testing me or anything.