New and so confused - B12 abnormally ... - Pernicious Anaemi...

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New and so confused - B12 abnormally high after being extremely low


Hi everyone, this forum has been very helpful for me up to now and I think you are all excellent at getting the information across as I am really at my wits end with my doctors.

I was diagnosed with low b12 levels in June 2018, my reading was 181, however I had been tested 4 years before and had a reading of 161 so essentially I had been deficient for 4 years with no help. Once the GP discovered this in June 2018 I was told I would have loading injections and then 3 monthly injections for life. I had my loading injections in July, then my first 3 month injection in October. After my first injection I had a blood test and on 11 October my reading was 369 (normal)......after this, my symptoms have been getting worse as follows (I know you've heard them all before so apologies):

Extreme tiredness and fatigue (can have 8 hours sleep and still have a 3 hour nap in the afternoon - unless I'm at work when I just have to suffer through!)

Tingling in legs and arms

Lack of concentration

Short term memory loss - this is particularly worrying me as it is affecting my job, I noticed it most when I was at a quiz night and couldn't recall the last question that had been asked each time (just an example!)

Palpitations and tight chest


Bad immune system - keep getting colds, had 2 in 3 weeks

I mentioned all these symptoms to my GP on Tuesday mentioning I'm worried it's all related to my b12 deficiency, she took one look at the screen and said my b12 is fine (I then had to tell her it's fine because I had an injection in October but I'm on them for life) - I was really upset at this point, in tears, as I had been talking about the memory issues and being constantly tired, etc. and she basically said she thinks I might be depressed (!!!).

She agreed to do some more blood tests and I have just checked the results which read as abnormal at 1099 :( - has anyone experienced this? I assumed my levels had dropped right down again (hence the symptoms I've been having) and I might need injections more often so for it to have gone up so high is quite a shock to me and I don't understand why this could have happened, surely in a normal situation the levels would go up after an injection then gradually come down until the next injection?

I apologies for such a long essay, I'm just so confused and worried on the basis the doctors don't seem to take any of this seriously!

Thank you so much in advance (and for all the information I have seen so far).


12 Replies

My daughter has this problem. She started much lower at 93 B12 level but a year in feels really tired ect before next injection. For her, folate was the problem. She takes supplements now as they kept stopping and starting her.

Also gave you tried another doctor?

It is very annoying when offered antidepressants if it is the physical health you want to get right then you won't feel down! !

I was prescribed prozac as must've been presenting as depressed before the blood test result I actually got them! but have not taken them now I know B12 106. So have had first loading dose instead.!!

I can't read your printed sheet of tests.

Look up each one to check the normal level. Also if yoor Hb low too what are you taking for that? Nutritionists can be helpful.

Hope you find the right regime soon

Njc15274858 in reply to Nackapan

Hi, thank you for getting back to me. I was told my folate was low so I've been taking folic acid tablets that the GP prescribed for that and it seems to be back to a normal level. Sorry, I'm not sure what you mean by Hb?

I'm definitely not depressed, like you say, I'd be completely happy if it wasn't for feeling rubbish all the time!

I have tried a few doctors at the same surgery (although they are mostly locums!) - the one before this week said that folate and b12 don't work together so can't be that that's making me feel bad (I instantly lost faith in him) and the one this week told me that if my b12 levels are now normal (i.e. when she read it at 369) then I should be feeling fine and it doesn't take time to feel better (clueless I presume from what I've been reading here?).

I just feel completely lost to be honest - it will be interesting to see if the Dr contacts me to go in about my high b12 level or whether I have to get in touch with them first

clivealiveForum Support

Testing of serum B12 levels after treatment has commenced is not necessary. (See bottom of page 5) where the 2 months interval of injections for those with neurological symptoms is also reiterated.

It is also important that your Folate level is monitored as this is essential to process the B12.

There is a complex interaction between folic acid, vitamin B12 and iron. A deficiency of one may be "masked" by excess of another so the three must always be in balance.

Symptoms of a folate deficiency can include:

symptoms related to anaemia

reduced sense of taste


numbness and tingling in the feet and hands

muscle weakness


Initially, replacing B12 will lead to a huge increase in the production of blood cells and platelets (which occurs in the bone marrow) and can lead to rapid depletion of folate and iron stores; this can then limit the expected recovery of Haemoglobin. Both iron and folate may be needed so please have these levels checked by your doctor.

I am not a medically trained person but I've had Pernicious Anaemia (one of many causes of B12 deficiency) for more than 46 years.

I wish you well.


the earliest result - in 2014 - looks like it was actually done with different units from later tests so not entirely comparable - though it was on the low side then and was marked as abnormal.

Are you sure that the october blood test was after the maintenance shot and not before.

A B12 shot should mean that your levels immediately afterwards would be off the scale and then they will fall over time - how quickly varies from person to person.

Your test results above look consistent with the October bloods having been drawn before the maintenance dose, not with bloods drawn after the shot.

Serum B12 is only really a useful test for diagnosing an absorption problem (eg levels dropping significantly - which is the pattern above) It isn't a test that can be used to manage an absorption problem and say you are okay after B12 loading doses. - however most GPs aren't aware of this and the guidelines available to them are far from clear on the matter.

Many people need much higher levels of serum B12 to function after loading doses - the exact reasons aren't clear, nor is why it affects some people and not others - though there is some interesting research going on through the PAS at the moment.

What seems to happen is that high serum B12 in some people makes the process that allows it to get into your cells much less efficient - and the only way to get round this is to keep the levels really high.

Some people find that very high dose sublinguals or nasal sprays - even skin patches - can help with keeping levels high enough between loading doses but this doesn't work for everyone (and is best started after a dose). If you can't get through to your GP then people do start self-injecting (sourcing B12 from on-line pharmacies in countries where it isn't prescription only.

I had a similar experience with my GP.

I’m taking methyl folate on recommendation from a response to my low folate levels discussed on here or thyroid group (along with self administered B12 injections as GP said in range but just). I recall folic acid is not as effective and needs converting...thus taking already converted more effective.

I’ve also read on here somewhere that you can feel rubbish initially when starting B12 as your immune system tries to sort itself out. Stick with it x

Njc15274858 in reply to LowB12

Thank you :) x

fbirder in reply to LowB12

For over 90% of people folic acid should be as good as, if not better than methylfolate. For the 9%, or thereabouts, of people with a certain genetic mutation (homozygous for C677T) methylfolate may be better.

Once methylfolate has been around the folate cycle once, it still needs to be converted, just like folic acid does. And each molecule will go around the cycle thousands of times.

Hi everyone, thank you so much for all your help and responses - I'm so sorry, I was mistaken and the October result was taken a day before I had my injection! So that makes sense that it's in the 300 range, I understand that levels can go up very high after an injection but in theory shouldn't my levels have dropped back down quite a bit as it's been over a month since I had the injection? My folate levels have been tested and are back to normal after taking folic acid, I just don't know why I feel so terrible, I'm barely managing at work, just want to sleep all the time and as mentioned, my memory and concentration is worrying me too.

I'm going to get an appointment tomorrow to see what they say about my results, I don't doubt they'll just tell me it's normal for it to be high between injections but that doesn't help with how or why I am feeling how I do.

I know it can take time but is it normal to get so much worse in that time?

Really appreciate the help :) xx

fbirder in reply to Njc15274858

As has been mentioned a few time, serum levels of B12 can be irrelevant once treatment has started. Some people need more frequent injections to keep symptoms at bay - despite having blood levels that are very high.

Nobody knows why this is, but the PAS is involved in current research looking into it. Early results indicate that they have found a biochemical difference between those who do need frequent injections and those who don’t. However, it will take many years for the study to be completed and for the results to be understood.

Until then we must suffer or resort to self-injection.

Hi, I’m also experiencing the neurological symptoms getting worse. I’ve had my loading doses and my first 2 monthly shot. Before the last one my levels dropped from the 2000s to 700, I had the shot and just over one week later I’m tingling in arms, legs and everywhere again. So back to the docs again for more B12, if she agrees. Looks like loading doses again, or weekly perhaps to sort this. So yes it can take ages to sort this out! I’m buying the kit to SI. Good luck with finding a doctor that can help you. I cross my fingers for you.

Hi Njc, I have had diagnosed PA for about one year now. Very similar pattern to you in fact. I now have ten weekly injections and folic acid supplements every second day. I don't worry about my VitB12 long as they are high. I take oral supplement VitB12 thousand ug about three tables, three times a day. I know this sounds so high doses but we absorb very little of the oral ones but I take it to keep my stores high if possible. Anyway, what I want to say is that some times I feel just like you, other days I am so well. I Definately now have many goods days but take the good with the bad. It's a complicated disease. It has taken a year riding this storm to say I have well times. My latest thing is pains in my legs particularly at night, so I gave my self an extra injections and took more supplements. Goodness knows if it will help but I slept better last night and woke without the anxious feeling I sometimes have. Hang in and better days will come, your body will have a lot of adjusting as you were low for so long...just like me. Xx

Thank you, I really appreciate that and sorry you're also going through feeling so terrible too :( Really appreciate everyone's help on here xx

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