[skboren]

Originally Posted by mrsD

Most test ranges are not kept up to date, and most labs have a ceiling test of 2000. They will report this as HIGH and some doctors --who are trained to fear anything HIGH-- think this is "bad". There is no evidence anywhere in the research that high serum levels of B12 are harmful in any way.

There is great information about B12 in this thread. This bit, however, requires clarification. Serum B12 values that are elevated out of range are in fact associated with a number of cancers and other life-threatening conditions. That doesn't mean that if you supplement too much B12 you're putting yourself at risk of those conditions. But it does mean that if your serum B12 is excessively elevated, it may be a sign of a cancerous or other serious condition that requires treatment ASAP. (I had a link to a reference, but it won't allow me to post the link, sorry!)