Tests are a waste of time and money IMO.
Almost certain is hypochlorhydria because that is almost always what causes SIBO. Until you get your stomach functioning you will have great difficulty stopping SIBO.
I would recommend Colloidal Silver ie particulate form and not the common Ionic form. The particulate form is far safer and more effective against stomach infections. You can make this yourself providing you regulate the current. You would then need to perform a reduction using a suitable reducing agent such as maltodextrin, Maltose or something else such as powdered Aloe vera extract. These need to be mixed with the prepared ionic silver and heated to eliminate the charged particles. I now have a magnetic stirrer/hotplate so this should all be fairly easy to do.
Reduced CS should help both the stomach and the small intestine. Just getting your stomach acid functioning will also clear up your small intestine.
I am about to try this myself although I must point out that I do not have SIBO because I raise my stomach acid levels. Things have been slow due to having to get various things. Plus I injured my foot last night which is making things harder. I hope that I have not broken a bone. It's badly swollen and hurts. I have broken that ankle in the past. I am hoping that it is just swollen and will clear up by itself. I will see if the swelling reduces in the next couple of days before going to A&E.
You could try doing a stomach acid test using sodium bicarb.
Another test us to swallow some acid such as lemon juice or vinegar and wash it around your mouth to mix saliva and then swallow. Have some sodium bicarb prepared in some warm water and wash it around your mouth to neutralise the acid immediately afterwards BUT DO NOT SWALLOW. Spit it out. Then see if you burp. Urease bacteria should neutralise the acid and cause a burp. Saliva contains Urea which is what these bacteria use. Therefore if you burp a lot, especially when you consume acids or your stomach tries to produce acid to digest protein, then you now know why!
Oops I forgot to put in the link
http://livingfoods.co.uk/the-acid-test-by-philip-weeks/