Welcome to the forum.
I agree with Quincy, the only test is a colonoscopy - that will definitely rule it in or out. I hope it's out for you.
However, while he's testing for ESR, let him also do a test for vit. d as well.
As you may be aware there is a correlation between IBD and low vit. d3, and although it isn't a predictor, if you find you do have low vit. d3, you can start to supplement with it.
Rx meds didn't help me. But 4.5 mg LDN +Paleo diet +supplements=REMISSION.Protein shakes w/almond milk,Maca powder,L-Glutamine,D-Ribose,chia seeds.VSL#3,K2,VIt. D3,slippery elm bark powder.For more info,my protocol is the 11th post at this link: https://www.healingwell.com/community/default.aspx?f=38&m=1666318
If you have any questions, you can find my email address at my profile.