Thyroid UK

Vitamin B12 results

Hi I have Hashis, any idea if my vitamin B12 looks optimal? I currently take B12 which is 1200mg in strength, is methylcobalamin and sublingual spray form. I have results for B12 going as far back as 2014.

JAN 14

VITAMIN B12 353 (180 - 900)

JUN 14

VITAMIN B12 361 (180 - 900)

JAN 15

VITAMIN B12 365 (180 - 900)

MAY 15

VITAMIN B12 384 (191 - 663)

OCT 15

VITAMIN B12 549 (191 - 663)

FEB 16

VITAMIN B12 698 (191 - 663)

MAR 16

VITAMIN B12 619 (191 -663)

JUL 16

VITAMIN B12 537 (191 - 663)

I started supplementing in Jan last year after I felt my vitamin B12 level was low. I have no idea why one lab would change its range from 180 - 900 to 191 - 663.

7 Replies

Yes, that is strange. Are you sure that it isn't the active B12 test? The upper limit is lower in that. The 180 - 900 range is obviously serum B12.

Yup, you're on the right track! Your B12 is rising nicely, and methylcobalamin is the right one.

Now, what about your vit D, folate and ferritin? :)


Hi and thanks, I think all results are the serum vitamin B12. Sorry I was going to include the ferritin, vitamin D and folate as separate ones but can put them here instead.


No, good idea to put them separately. :)


Unless you deal with the lab directly or they have put on your results something like please note new range, it may be a different lab.


Still too low to be optimal - aim for 1000 - I know it's over range, but it's what the Pernicious Anaemia society recommend.


Once you are supplementing B12 the test is of little or no value. Do you still have symptoms - or what were your symptoms before you started supplementing ?

It is laid down in the Guidelines for Folate and B12 Deficiency that further testing is of little value. Your GP should have read them. The results are skewed as it tests the B12 in the blood and not the B12 in the cells - ( no test for that ) B12 is needed in the cells .....

The range in Japan starts at 500 :-)

1 like

What are you actually supplementing with and at what dose? It shouldn't take 2 years to raise your B12 by such a small amount. You're either not taking the right stuff or not taking enough.


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