Uses of stool samples

I've had active, unremitting UC for over a year, and this is the first time I've been asked to provide a stool sample. Not at diagnosis, never even had to give one when I was hospitalised. I know most of you here say they're to check for C diff, but I've never even heard of C diff outside this forum, and my GI didn't mention that as the reason. In fact she told me to provide a sample after I bummed hard when she suggested a flex sig.

Surely if they were only testing for c diff infection I would have been tested before now. Is there any information in a stool sample that could allow me to avoid having this flex sig? I really do hate them and want to avoid it at all costs.

They could be looking at calprotectin levels. Thats one (not always trustworthy) way of testing for active inflammation