I've posted on here a few other times and have honestly felt like the advice I've received here has been more helpful than many of my doctors' appointments!
Quick summary: Went to a new GP in a new city in July with immense fatigue, joint pain, difficulty concentrating, etc. As I am a vegetarian, I had been on daily oral B12 tablets. My B12 tests from that appointment came back around 200, which the doctor thought odd since I had been taking tablets. Further tests revealed a positive intrinsic factor antibody (although negative for parietal cell antibody). GP gave me 1000 mcg/mL B12 shots. I self-injected once a day for 7 days, then once a week for 2 weeks. I noticed after the month of this that I felt marginally better, although not fully. At that point, I had a hematologist appointment, and she said that because my gastrin wasn't elevated and because I didn't have anemia, the intrinsic factor antibody test had likely been a false positive, and I should immediately stop the injections.
That was towards the end of September, and I haven't had a shot since. I've noticed the fatigue returning, although it isn't as bad as it was right before I injected. I saw a new GP since I didn't like the first one, and she thought it was odd the hematologist had been so dismissive, so she retested. B12 now at 400, and NEGATIVE intrinsic factor antibody test.
I'm really confused--this GP is fairly open, and wants to recheck my B12 in 6 months. I'm really afraid it will get worse like it did before the injections during this time, though. Is B12 at 400 a normal rate for someone who injected 9 doses of 1000 mcg/mL of B12 6 weeks ago? Could the intrinsic factor antibody test be a false negative the second time? I'm just not sure what to do and would welcome any advice.