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Calprotectin and Miscroscopic Colitis?

Hi all. I'll get straight to my main question before I jump into some backstory: Does a negative fecal calprotectin test rule out microscopic colitis?

Now- if you're interested, here's some backstory. I'm a 22 year old female with type 1 diabetes and thyroid disease. I've had IBS for as long as I can remember. Excruciating pain, hours on the toilet covered in sweat, sorry for the image, but it's horrible. For a long time I had IBS-C and about six months ago it completely just changed on me. I now have severe IBS-D. Many foods I eat come out completely undigested, just as I ate them (I know this is common with IBS). The pain and suffering is unreal, even compared to how it used to be. Lately I just haven't been able to wrap my head around the fact that this is IBS. Each day hours are spent on the toilet ready to pass out. I went to my GI doc and he ordered a fecal calprotectin test which I just found out was negative. Previously I had a colonoscopy 2 years ago where pre-cancerous polyps were removed and no inflammation was seen, and another in December which was clear. I have a family history of IBD- my grandma has UC. I have an appointment with my GI doc in a couple of weeks and it would be great if I could get some suggestions on what I should ask him about or request.

my little penguin

Staff member
A lot can change in two years
Anything more than 6 months tends to require a new set of tests
Ds primarily has constipation
His fc is generally low to normal
His bloodwork tends to look great
Scopes look visually normal
But biopsies show chronic and a it inflammation throughout his gj tract
Upper and lower plus granulomas so crohns dx.

My point one test does not prove you don't have Ibd


Super Moderator
If you're suspecting microscopic colitis, then biopsies of the colon are your best bet (since it's microscopic AND has a skip pattern, they can't see it and basically need to luck into biopsying the right spot, so the more biopsies they take, the better the odds are of finding it). I agree with MLP, if your last colonoscopy was almost a year ago and things have changed/worsened since then, it's probably time to have another one with lots of biopsies. Pill cam could be helpful as well to rule out or confirm whether anything is going on in your small intestine.

And for what it's worth, my GI has suspected for awhile that I have microscopic colitis (I'm undiagnosed, I seem to have some form of IBD but not sure which one since it likes to hide on tests) and my calprotectin was only tested once but it was normal as well. It was actually frustratingly normal - my calprotectin was 49 and apparently anything under 50 is considered normal. Ugh. So I feel your frustration!