That figure only represents that fact that you have a lot of B12 floating around in your bloodstream--it doesn't represent what you are using on a cellular level. That is much harder to determine, but however much that is, you want a lot of available B12 in the blood, so keep that level nice and high.

There are some negative conditions that might cause high serum B12 levels, so just make sure you tell any doctor that you are supplementing heavily.

My last reading was 1864--I take 2500mcg methylcobalamin each day, and get some cyancobalamin from the B-complex I take. Even though I did not have indications of B12 deficiency, like many a neurologic patient, I find high B12 levels to have a neuroprotective effect, and I'm going to keep the levels as high as I can, inasmuch as B12 has no known toxicity and it's relatively cheap to supplement orally. (My 5000mcg sublinguals, which I split one at a time, sell for $7.99 for 60, so that's a four month supply. Comes in under $25 each year--there are few things that can be so helpful that are so cheap.)