Calprotectin levels 'ARE' an indication of inflammation somewhere in your GI tract, and the fact that yours was 1800, and mine was 1400, indicates that at that time the sample was taken we both were showing signs of high inflammation in our GI tract. The GI tract is specifically described as any part of your digestive system from the mouth to the anus. My blood samples have never shown any signs of inflammation either, one doctor said to me that an IBD will usually give raised white cell counts during a flare up period. My symptoms are exactly like yours, only mild, sometimes moderate stomach discomfort, discomfort when needing to pass wind or have a bowel movement, I don't get fevers, weight loss or loss of appetite, however I hardly ever bleed now, and if I do its a few spots on the toilet tissue when wiping. Bloody, loose stools can be a sign of IBD.
I was probably wrong in saying that I don't have an IBD with my calprotectin levels at 1400, what I should have said was that they haven't discovered IBD yet. I've had 3 separate doctors views on my problems, two have said that they would not consider IBD to be a factor in my symptoms, however one has said he would remain open minded and would look into further investigation, this has now left me in limbo, and wondering if I should pursue this further or accept my main doctors diagnosis of IBS and haemorrhoids, which were found during my last colonoscopy (I have been diagnosed with Fibromyalgia and CFS as well, which would account for my other symptoms). My doctor also said that if I did have an IBD then I would, at times, be feeling much worse than I do get at present.
One thing I have learnt is that there is a whole host of factors that can cause raised calprotectin results, gastroenteritis, gastritis, stomach ulcers, NSAID's, food intolerances or allergies, inflamed haemorrhoids, plus others I'm sure, so the likelihood of the raised calprotectin results being IBD related are therefore reduced significantly, but that doesn't mean it's not a possibility. I have recently been tested positive for the following food intolerances, cows milk, sesame seeds, yeast, tuna, millet and wheat. Since eliminating these foods I have noticed a slight improvement in my symptoms, however I've only been eliminating for 2 weeks so far, so it is early days still.
Your doctor is right to treat your problems seriously now, personally they should be treating all of us seriously from the start. I do hope you get investigations into your problems under way soon, and you get the results you are looking for. Be prepared for a long haul when it comes to getting a confirmed diagnosis, I've heard of some people having to wait up to 5 - 6 years for a diagnosis, I've been waiting 3 years now and I'm still none the wiser, even though plenty of people have said that I should trust my current diagnosis.