I don't know how I would tell. Not only are there overlapping symptoms but there may be similar etiology. Apparently a lot of people with interstitial cystitis which.can be triggered by ketamine also have chronic utis , there is controversy about that.I did not know that ketamine can affect the bladder, but I just learnt that it can. And it looks like it can turn into a potentially irreversible issue called ketamine bladder syndrome (aka ketamine cystitis). This article says:
I guess the question is, do you have this ketamine cystitis, or just an UTI?
When I searched for stuff on the overlap it seems like many ketamine users think they get utis caused by it.