Docs can easily be fooled by the lab reports because they are used to thinking things are fine if the lab says the level is "normal." But in the case of B12, "normal" does not mean "healthy" and it does not mean you are not B12 deficient. Patients with B12 of 100-200 are in the "normal" range, but about 50% of these patients are B12 deficient.
The typical B12 test is not designed to rule out B12 deficiency, but only to say what is "normal." One of the links I supplied goes to the American Family Physician document, which suggests that, if you have a B12 level of 100-400, you can be further tested to rule out deficiency. These tests are the "serum methalmalonic" and "homocysteine levels." If either level is elevated, you are definitely deficient.
But in the US, endocrinologists don't bother with the additional tests. It makes sense to suspect anybody with less than 300 is deficient, and needs a shot to quickly build up the B12. And then to follow up with lab work to make sure the levels have risen enough. The problem is, either you are deficient or not. There is no such thing as a little deficient when it comes to B12. My daghter has never had surgery, has no symptoms, has no scar tissue, but just cannot absorb enough B12 through the oral route.
The oral route is worth trying, but even if it works, the body can only absorb a miniscule amount, at a time, of the supplement. This is why docs tend to go for the shot if B12 is lower than 300, to quickly boost B12, rather than risk the harm that can be done by B12 deficiency.
So the shot might make sense at least initially...I don't have Crohn's and my own B12 was 239 (I worked night and day and didn't eat right.), so I got the shot and have been able to maintain via the oral route. Maybe this will work for you...the only way to know for sure is trial and error, and following up with labs to check what is and isn't working.
Post Edited (njmom) : 7/22/2010 11:04:28 AM (GMT-6)