Pernicious Anaemia Society

Would multivitamins with B12 mask a deficiency?

I've recently been told I have a B12 deficiency and macrocytosis. Main symptoms are fatigue and depression. Blood tests showed B12 level of 83, so I was given 6 loading jabs which put the level up to over 2000! Unfortunately, I don't feel any better, and I've felt this way for years. I used to take multivitamins every day for many years and wonder if they could have prevented a deficiency being picked up in earlier blood tests. Any help would be appreciated, thanks.

4 Replies

Blood tests in the UK don't routinely look at B12.

Do you know what your folate (B9) levels are like - this can affect how the B12 is actually processed. Unfortunately there are different forms but again, tests in the UK don't look for the active form.

Unfortunately some people don't feel better for the shots - though there isn't a clear reason for that - though there does seem to be evidence for an interaction with B9. I think it is dubious that taking B12 supplements would have made a difference as the problem sounds as if it is absorption of B12.

You may find looking at the PAS website helpful - though generally you need to join to be able to see a lot of the more useful stuff.


Taking multivitamins that contain B12 would only mask any actual B12 blood tests that you may have had. You would get a higher result of B12 in your bloods as a result of taking it in any supplement form but would not be making any use of it or feeling any benefit from it as I presume that you have a B12 absorbency problem as many of us do. Having such a low deficiency would certainly account for how you are feeling, my results were also in the low 80's when I was diagnosed 3 years ago. Has your folate been tested? It is vital that you have adequate amounts of usable folate in your system in order for the B12 to be used efficiently. Many of us need our folate to be on the top end of the ref range scale to feel better. I am still having to take folate on a daily basis over 3 years later as I still need to inject once a week. I cannot survive on anything lower than this.

To get all of the information that you need, that is personal to your situation, it would be very helpful for you to join the PA society. This way you can ask all relevant questions and get the answers that you need from some very experienced people. They were invaluable to me when I was first diagnosed and have really helped me to improve my quality of life.


Sorry for the delay replying back - I had notifications turned off, so wasn't aware!

Serum folate was 15.3 (4.8 - 19), which seems ok.

My energy levels have picked up quite a bit, now, so maybe some new red blood cells are doing a better job of taking oxygen around the body...

My GP also said that I am NOT anaemic - how, exactly, is that determined?



Regarding achieving accurate results from B12 blood test:

Here is the answer I received from an accredited source re how long a person should be off B12 Supplements prior to testing for their B12 level.

"Welcome to the American Society for Clinical Laboratory Science consumer information website. Questions posted here are answered by a group of laboratory professionals from around the country. We volunteer to try to help patients and their families understand laboratory tests and their interpretation. Thank you for asking your question at this web site.

Half-life of B12 can be between 3 days and 6 days, depending on the form that you are taking. It is recommended to stop taking B12 supplements about a week before the testing. I would also suggest asking your specimen collection site to include a comment that you are taking B-12 supplements before your specimen is drawn for testing."

This information was provided by Maja Chloupkova, ASCLS Consumer Information Website Response Team,

I'm new to site and finding it helpful.

Thanks, Leilani


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