[mrsD]

There is no upper limit on B12 medically. (not toxicity studies)

The out of range upper figure is only useful for those patients NOT taking any supplements before the testing. The ranges were
developed on people not using any supplements, currently or in the recent past.

So the upper readings out of range can imply some medical condition (kidney failure, some cancers, liver disease, etc) being present, that needs further evaluation.

Excess B12 that is not used, or stored by the liver is excreted by the kidneys.

However, some doctors react to high B12 readings with horror...and tell people to stop supplements. This indicates a poorly trained doctor who doesn't understand the test's meaning. I myself would find another doctor who can evaluate things more realistically.

[Auntie Audrey]

Hello skboren, the “bit” you highlighted from mrsD did not in fact require any clarification as you took the quote out of context. As mrsD said, there is only a problem if your B12 levels are excessively high and you are not supplementing with it.

By the way, it is not good form to join a group to ask for advice one day and then criticize the most knowledgeable member of the forum the next day.

[skboren]

Originally Posted by Auntie Audrey

Hello skboren, the “bit” you highlighted from mrsD did not in fact require any clarification as you took the quote out of context. As mrsD said, there is only a problem if your B12 levels are excessively high and you are not supplementing with it.

By the way, it is not good form to join a group to ask for advice one day and then criticize the most knowledgeable member of the forum the next day.

I'm sorry. I didn't mean to offend anyone and I wouldn't want to criticize MrsD. I can see she is soooo helpful to so many people on this message board! I just wanted to point out that there are conditions associated with elevated B12, because one of those conditions might possibly be present EVEN in those who are supplementing B12. I could also see someone with PN getting their B12 checked before they begin supplementing and seeing an elevated result and thinking that it was fine, so I would want them to know about these conditions. I meant no harm or criticism.

[mrsD]

Nothing in medicine is 100% accurate or perfect.

Gosh, even the testing can be flawed itself. The calibration of the instruments may use old "knowns" and end up messed up completely. Quest had TWO episodes of wrongly calibrated Vit D testings in the past. One was not discovered for an entire year...so all of those tests were inaccurate!

There are far more people missed who have low B12, (ignored even) than who have an elevation pointing to a cancer or kidney failure. The chem screens on the blood would reveal kidney, and liver problems, and CBCs would show aberrations for anemia or whatever. So the high B12 would only be another test, which often is not used anyway.

[Patrick Winter]

Originally Posted by mrsD

Nothing in medicine is 100% accurate or perfect.

Gosh, even the testing can be flawed itself. The calibration of the instruments may use old "knowns" and end up messed up completely. Quest had TWO episodes of wrongly calibrated Vit D testings in the past. One was not discovered for an entire year...so all of those tests were inaccurate!

There are far more people missed who have low B12, (ignored even) than who have an elevation pointing to a cancer or kidney failure. The chem screens on the blood would reveal kidney, and liver problems, and CBCs would show aberrations for anemia or whatever. So the high B12 would only be another test, which often is not used anyway.

Blood cell counts are are much more indicative barometer to judge cancer by. If those are in line a high b12 should be of no concern. Especially if it's from someone on a b12 supplement

[Patrick Winter]

Originally Posted by mrsD

Nothing in medicine is 100% accurate or perfect.

Gosh, even the testing can be flawed itself. The calibration of the instruments may use old "knowns" and end up messed up completely. Quest had TWO episodes of wrongly calibrated Vit D testings in the past. One was not discovered for an entire year...so all of those tests were inaccurate!

There are far more people missed who have low B12, (ignored even) than who have an elevation pointing to a cancer or kidney failure. The chem screens on the blood would reveal kidney, and liver problems, and CBCs would show aberrations for anemia or whatever. So the high B12 would only be another test, which often is not used anyway.

What about hydroxocobalamin form of B-12? I am seeing in some places that it may actually be even more effective and potent than methyl version of B-12.

[mrsD]

Hydroxocobalamin is still an inactive form of cobalamin in the body and requires conversion.

http://centraldrugsrx.com/doctorblog...of-vitamin-b12

This link explains the 3 forms available, cyano, hydroxo, and methyl.