Only took 11 years ¬_¬
To be fair, in the first five years of having Crohn's there probably was no need. But once symptoms started worsening and I developed iron-deficiency anaemia, you think it might have occurred to somebody to test my B12 level as well. But no, it took until today and me bringing it up to my GP. I actually asked him why nobody had ever tested me for deficiencies other than iron before, and he did actually admit that somebody should have done; that he could have done it but it never occurred to him. He actually sounded slightly ashamed, a reaction I didn't expect from him :-/
So, I'm due to get tested for B12, folate and calcium when I go in for my second iron transfusion. I didn't push it beyond that. If I'm deficient in those things, then I can request further tests, eg vitamin D. But if I'm not there's probably no point in getting further vitamin/mineral tests. My GP did say that if those three things were all right, then the other stuff - magnesium, potassium, etc. - tend to be as well.
Also, I've been referred to a psychiatrist... :-/