Bear in mind a flare could have been brewing for months before you started to experience symptoms.
And this is why they aren't spontaneous or that blood isn't the first symptom of a flare.
Changes arent noticed until they're a bit more obvious...then we suspect, cross our fingers, wish it away or justify it. However...some wait till blood appears even though symptoms aren't that bad but obvious. Still flaring, however. Recognising the confirmation earlier is a good thing so that we can treat earlier if symptoms are consistent or increasing. I don't depend on my doctor to tell me yea or nay.