Re: Will a B12 blood test one day after an injection appear falsely high?
I'm sure you'll hear from others on this board who have lots of experience with B-12 issues. I can only give you my experience. I saw my doctor for anemia and she elected to give me a b-12 injection. The injection was given first, then within 15 minutes my blood was drawn for testing. The resulting B-12 value was off the scale at >2000. My doctor told me to wait one week before coming back for a recheck, it was still high at 931 (range 211-911). Two months later it was near the high end of normal at 816, which is probably typical for me. Obviously my B-12 level was not contributing to my anemia. So from my very limited experience, I would think your B-12 levels would still be quite high on the day following your injection. I wish you the best and good luck with your treatments.