There is mucus-like blood in my cats stool.?

I have two cats, a male and a female. They're both around 1 year old give or take a few months. Recently my male was diagnosed with a possible case of IBS and was put on gastro intestinal food to help his poops solidify. Recently, however, one or both of them have been pooping outside the litter box, half a foot away in front of my dryer. I've been dutifully cleaning it up, scolding them, and putting it in the litter box. Today, however, I noticed that there was bit of blood in the mess, kind of viscous. My roommate (who admittedly cleans up more then I do as she is home more often) said that she's noticed if for a few weeks and didn't think it was important. I'm making a vet appointment tomorrow, but I'm wondering if its an emergency like thing.