Pernicious Anaemia Society
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If you have normal active b12 but low blood serum that ok?

I'm hoping someone might be able to throw some light on this. My serum b12 is about 250 but my active b12 is normal at about 69?

What is a good level for active b12?

Do we go by the active b12 level or the serum b12?

And if the active looks ok do we then ignore the low serum level?

Sorry.....a lot of questions I know!


5 Replies

Perhaps a more pertinent question would be for us (me) to ask you - why did you have the tests?


Well, my serum b12 was 300 and the doctor thought it was too low. He didn't do active. I have had continual pins and needles in the tip of my tongue for a year or so. I'm also hypothyroid.

I took myself off and had the other tests done privately. Serum b12 had dropped lower.


Okay, the tip of the tongue pins and needles is a new one on me - but I don't doubt you!

There are problems with all of the tests.

I've always had niggling issues with the active test. Not least that I was aware early on that there had been no studies performed with actual patients. So you have a situation whereby everything is being measured in the laboratory against other test values - that are, quite possibly, measuring the wrong aspect of the illness anyway. I also know that it can be affected by people with renal (kidney) problems and type II diabetes. So, you pays your money....

I asked why you had the tests simply to see if you thought you were symptomatic.

Maybe it would be a good place to start to identify if you have other symptoms that you didn't realise were related to a b12 deficiency:

This is interactive and gives you a score as you go along.

.... and if your doctor thought your serum b12 was low, did he treat you? If not, why not?

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Also another test may help decide, MMA, but its not cheap, homocystein can help. But you symptoms can also be caused by heart problems/ folate def/ potassium level to low or to high, other vitamin def (E etc), so not something to ignour I would have thought.. Marre.

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Thank you Marre, that's very helpful. Will get some other levels checked.


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