I had 18" removed at my TI. I do monthly self injections of B12. I have issues with many vitamins due to that area being removed. I sometimes stabilize to good level of B12 on my lab work, but if I go several months without injection, I drop way down again. I find its best to keep my maintenance. I can always tell when I am due for my shot as i get very sluggish and my tongue feels swollen. I am very pale skinned to start with, but I seem to get even more pale right when i am due too.
Dagger - My B12 issues do not show on every lab test. As I noted above, sometimes it will level off and look good for a period of time.