Thyroid UK
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Active Vit B12, Ferritin and Folate results, help please!

Trying to sort out my recent palpitation problem, I have had some private bloods done and have posted about various aspects of the tests previously. I would love to get some advice about B12/ferritin/folate results. All these are without supplementing:

Active vit B12: 120 pmol/L (25 - 165) [equiv to 162.6 ng/L]

Serum vit B12: 383 pmol/L (250 - 750) [equiv to 519 ng/L]

Ferritin 131.5 ug/L

Serum folate 17.97nmol/L (10.4 - 42.4) [equiv to 17.97nmol/L

My query is, should I be supplementing these? It is very interesting that all the results are higher than a year ago. I started a gluten-free diet about four months ago and have been eating liver once a week (ferritin May 2015 was 63ug/L). The only supplements I take at the moment are Vit D, Vit K, selenium and magnesium, either as Mg taurate or as the spray oil.

6 Replies


Active B12 is very good, but serum B12 is low. I'm not sure which you should go with so if you don't get definitive advice here post on the PAS forum for advice.

Ferritin 131 is usually good as is folate 17.92 and neither need supplementing.


I am not a medical professional and this information is not intended to be a substitute for medical guidance from your own doctor. Please check with your personal physician before applying any of these suggestions.


Thank you Clutter. It was interesting having the two B12 tests done together with the same blood (Blue Horizon). I'm glad I didn't supplement before I tried gluten free. I can't think of any other reason why my levels of these three would go up (apart from starting to eat liver for the ferritin). Just a point re folate: the result should have read '17.97nmol/L equiv to 7.930ug/L'. As my result was in the bottom half of the range (up from 4.9ug/L May 2015) I had thought I might need to supplement - or wait a bit to see if gluten free continues to improve absorption.



Active B is the preferable test and result, as one-quarter of circulating cobalamin (vitamin B12) binds to transcobalamin (holoTC - active B test ) making this the available "active" amount for the cells use. Your level is good.

Ferritin is good over 70 but can't comment on folate as can't remember ! ! ! ... (brain foggy ) ...


Active B12 is a better test than serum B12 as it is looking at the pressence of the forms that are used by cells. However, both tests are looking at what is going on with B12 in your blood but it is what is going on at the cell level that really matters and even if you have plenty of active B12 that doesn't guarantee that enough is really getting to cells.

Folate is okay but ideally it should be upper half of the range.


Thanks gambit62. Couldn't the same be said of any serum reading of any vitamin or mineral, active or otherwise?


For some probably - however the biochemistry of B12 seems to be particularly complex.

High folate levels can be an indicator that your body is having problems converting it to the forms needed at the cell level so the folate is staying longer in the blood.

It's probably less true for vitamins that can't be stored in the body and unlikely to be true about that relate directly to the function of blood - such as iron levels and potassium but I'm not a biochemist.


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