The serum B12 numbers can be all over the place, as they only measure the B12 available in the bloodstream. A low number is bad, of course, as that would mean there isn't much around to BE used, but a high number doesn't guarantee that the cobalamin is making it into the methylation pathways (that's what the MMA--methylomaic acid--test helps determine).

On the other hand, I imagine a good deal is making it into Melody's metabolic pathways, as she does have a significant reaction from taking B12.

It's possible Mel's system is now flooded with B12 and she could make do with a little less dosage. I know that when my B12 serum levels were measured at 1864, I cut down from 2500mcg/day to 1000mcg/day, without apparent ill effects.

I wonder what Mel's levels would've been if she hadn't stopped taking the methylcobalamin five days before the test.

Seriously, though, my wife's PCP once questioned her high B12 levels (they're not quite as high as mine, but she takes less), and I immeditely asked, "other than masking a possible folate deficiency--and you can see my wife's folate levels are quite good--is there any known reason that a high B12 level should be cause for concern, especially when the level is explained by the patient knowingly supplementmeting with large doses?" The doctor couldn't answer, and I said "the reason you're having trouble coming up with this is there is no known B12 toxicity level--in fact, some European and Japanese studies have dosed people with neurologic disorders up to 36mg a day with no ill effects . . ." and the doctor started to laugh (they learn about me very quickly).

I think you can try asking them that question, Melody--let's see what answer you get.