The 'Trio Smart' breath test is the only commercial breath tests to test for hydrogen sulfide. They claim the test to be “at least equivalent to conventional breath testing for assessing bacterial overgrowth”, but that's not very comforting given the unreliability of the other breath tests where GI dysmotility is involved in the picture.I don't think that hydrogen sulfide is tested for in standard SIBO breath tests - perhaps it should be.
Not that the presence of hydrogen sulfide gas demonstrates any 'cause and effect' from bacterial overgrowth though as the gas can be produced by the host as a protective measure by the mucosa in the GI tract rather than be any by product of microbial breakdown.
I mentioned gas capsules earlier in this thread, Australian company Atmo Biosciences are developing the capability of testing for hydrogen sulfide with their Atmo Gas Capsule, and have begun recruiting gastroparesis patients here locally (Sydney) for a clinical trial of the device. It appears to be that it's as much about comparing its results against that of the gold standard 'Smart Pill' capsule though.