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Pernicious Anaemia Society
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Hi, I'm looking for advice on b12. I have been experiencing a sharp pain in my chest area since October with dizziness, light headed, poor memory, irritable, bad eyesight & my balance is sometimes off. On the second visit to the doctors they did blood test & called me the following day to tell me my results were fine apart from my b12 which is low at 124, but I am not anemic. She said my red blood cells are enlarged so they don't carry enough oxygen? Does this sound correct? They told me I would need b12 injections of 6 shots in the first 2 weeks then 1 a month for a year. I've moved house & can't drive so I asked if I could register with a new doctor that I can walk to & have the injections there. They said I could as long as I do have them. In between the three week wait I started taking b12 suppliments. When I booked an appointment at the new doctors she told me I would need 1 injection a month which is not what the first doctor said. I requested another blood test to see if my b12 level had increased with the suppliments. I've just received a phone call from her & she said that the lab won't do another b12 test as the first one is valid for 88 days do they have to go off that. She I don't need injections as my red blood cells are not enlarged & to have another blood test at the end of April. I'm confused with the conflicting information from the two doctors going off the same blood test results? I'm a vegetarian so don't eat meat so are the suppliments enough to boost the b12?

18 Replies

Hi Dobbins. Hello and welcome.

Your first doctor is right. Low vitamin B12 can cause large red blood cells (macrocytic anaemia) and the treatment for B12 deficency is B12 injections. (6 x loading doses on alternate days and then an injection every three months). But...also wrong because...

You have neurological symtpoms so you should be on a more intensive regieme of B12 injections - after the loading doses it should be an injection every other day until no further improvement - for up to two years. (I'll put some links in at the bottom of this reply - there's a symptom checklist in there somewhere so,you can see exactly what neurological symtpoms are). Your GP may not know about this regime. It's important that you have this regime to prevent potentially irreversible neurological damage. All the guidelines state that treatment with this regime should begin immediately if neurological symtpoms are present. Look for the UKNEQAS B12 Treatment Alert in the links below - print this off and show it to your GP - it's an instruction to treat immediately where neurological symptoms are present. (Also see the BNF Treatment Guidelines in the links below).

About the one year duration - not sure where that comes from...unless...if your B12 deficency has a cause that can be removed (for instance, such as a drug that inhibits B12 absorption - PPI's being one) then the treatment should continue. This would certainly be the case if a specific removable cause has not been identified. The most common cause of B12 deficency is an absorption problem and as such, not 'fixable'.

About the lab test - some do refuse to do tests but as you already have a proven deficency there's no necessity to get the test re-done. Another reason not to have the test again is that you have been taking oral supplements. This will raise your B12 levels slightly and may nudge your B12 level into the bottom of the reference range. Your GP will then refuse to treat you, assuming all is well. Wrong. You have had a confirmed B12 deficency and you need to get your B12 levels up quickly so that neurological repair can begin to take place - this will not happen if your levels are sitting at the bottom of the reference range - where they will stay if your GP does not treat you.

To put this in context - neurological symtpoms can occur at B12 levels below 500 (and even higher in some people), neurological repair takes place at levels over 1000, people on B12 injections can have very high levels - mine run at over 2000 and we have seen them here at over 5999 - off the top of the measurable scale. So, as you can see your level of 124 is very very low.

B12 deficency should always be treated - even in the absence of macrocytic anaemia or a confirmed PA diagnosis.

Also - the golden rule with B12 deficency is treat the symptoms, not the blood results - another thing your GP does not know.

Another thing about oral supplements - these are not recommended for treating B12 deficency with neurological symptoms - for the reasons outlined above. Only injections will do the trick.

Your second GP is wrong to assume that you don't need B12 injections because you no longer have enlarged red blood cells. 30% of people who have the symptoms of B12 deficency present without enlarged red blood cells (macrocytic anaemia) and may also have neurological symptoms - and this can occur without having a diagnosis of pernicious anaemia. Not many GP's know that. And you have neurological symptoms, so you should be treated immediately.

The simple fact is that you have blood test results that confirm you have a B12 deficency. You have neurological symtpoms. You should be treated with B12 injections. Immediately.

Did either GP test you for pernicious aneamia (anti-IF antibodies blood test). If not, ask them to do so. (You can have PA without having macrocytic red blood cells - your GP may not know this).

Did either of your GP's test your folate levels? B12 and folate work together so if you folate level is low then the body cannot utilise B12 properly. Folate level needs to be in the top third of the reference range for optimum effect.

Also - people with B12 deficency most often have absorption problems so can have other deficiencies as well, which can make you fell very ill.

Ask your GP to test vitamin D, magnesium and ferritin (ferritin is a protein that binds iron so that it can be absorbed by the body - low ferritin is indicative of iron deficency aneamia - this is one result that GP's often get wrong. Ferritin levels need to be 80 - 100 or at the middle of the reference range. So...be aware that...

GP's often say blood tests are 'normal' when they're not. Bumping along at the bottom of a reference range is not good enough for some things. It's a good idea to always ask for copies of your blood test results. Post them on the forum together with reference ranges and people can help with interpretation.

Anyway Dobbins...B12 deficency is a tricky and complex condition, little understood by most GP's. So you've come to the right place for help and support. Post any questions you have, ask for help if your GP won't treat you - we can offer more advice on that. And...read the information in the links below..it's the only way to know what your GP should be doing...and it will help you to get the treatment you should be having. And you do need this very soon....or as the guidelines say...immediately,

Good luck with your GP. Let us know how it goes. Here come the links:


b12researchgroup.wordpress.... (Serious Caution Note about the use of Oral and Sublingual B12 Supplements)

evidence.nhs.uk/formulary/b... (BNF B12 Deficiency: Hydroxocobalamin Treatment Regimes)

pernicious-anaemia-society.... (PAS Symptom Checklist)

stichtingb12tekort.nl/weten... (BSH B12 Deficiency / PA Diagnostic Flowchart)

onlinelibrary.wiley.com/doi... (British Society Haematology (BSH) Guidelines: Treatment of B12 Deficiency and Folate Disorders)

onlinelibrary.wiley.com/doi... (UKNEQAS B12 Treatment Alert, Neurological Symptoms and Risk of Subacute Combined Degeneration of the Spinal Cord)

stichtingb12tekort.nl/weten... (Problems with Serum B12 Test)

stichtingb12tekort.nl/weten... (Testing B12 During Treatment)

stichtingb12tekort.nl/weten... (Misconceptions About B12 Deficiency – Good to Know Before Seeing GP)

stichtingb12tekort.nl/weten... (B12 Treatment Safety / Long Term Treatment for neurological symptoms)

stichtingb12tekort.nl/weten... (B12 Deficiency: Neurological Symptoms Can Present Even When B12 is ‘In-Range’ and Without Macrocytosis (large red blood cells) or confirmed PA Diagnosis)

stichtingb12tekort.nl/weten... (Methylmalonic Acid – MMA)

stichtingb12tekort.nl/weten... (B12 Deficiency and Neuropsychiatric Symptoms)

ncbi.nlm.nih.gov/pmc/articl... (No Superior Forms of Cobalamin)



All these links can be a bit daunting but take your time, I also have been recently diagnosed and is a lot to take in! I refer back on many occasions (the brain fog doesn't help) on the links so I can read and understand them! Bookmark them, for future reference. Research is the key, and of course questions, which incidentally, are answered mostly on this forum! Thankfully!


Good point Greenbexy. Perhaps I should include a 'warning' or maybe a prescription 'take one, three times a day - with one hours sleep post-read' 😄. Or perhaps 🍷🍷 (for those who are lucky enough to still tolerate the odd sip sip 😖).

Trouble is...as you say...information is key to everything. But oh, if we only didn't have too..be much better if doctors would read this stuff...here's hoping 👍

P.s most of the documents in the links are one page. Exception is the BSH Guidelines - best eat that little elephant in chunks.


are you based in UK or US or ....?

Treatment protocols do vary by country - in part because different types of B12 can be used in the treatment.

If your red blood cells are enlarged then that means you have a type of anaemia that is called macrocytic or may be megaloblastic. The red blood cells have become deformed because your body doesn't have enough B12 to to make them properly and they are larger and rounder than normal - this means that the surface area to volume is reduced and it makes them less efficient at picking up and transporting oxygen from lungs to cells where it is needed. This type of anaemia can cause the symptoms you mention but B12 deficiency can also cause these symptoms because it is key to a number of processes in the body.

Iron based anaemias tend to make the cells smaller

What was the strength of the tablets you were taking? Depending on strength and whether the cause of your deficiency is an absorption problem or just dietary they could have an effect. B12 is found in animal products - meat, fish, dairy and eggs so not eating meat doesn't mean that you don't have enough B12 in your diet. It is also found in a lot of breakfast cereals as an additive.

What is confusing me is that one doctor seems to have said you have enlarged blood cells and the other says you don't based on the same test results. Suggest that you ask for a copy of the test results.

As Foggyme says GPs and many specialists often don't know much about B12 and are often very confused about how it works and how to treat it. Many still mistakenly believe that it is all about macrocytic anaemia though at least 30% of people with a deficiency present with neurological problems long before anaemia develops.

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Yes...I was confused by that too. Did wonder if the new GP ran a new FBC...and perhaps the small amount of oral B12 was enough to bring the MCV etc. to the top edge of the range - which was then considered 'normal'. Or perhaps it was at the top but just within range...and the previous GP had interpreted that appropriately as more macrocytic than not.

But really...never can tell with these GP's - normal seems to be a bit of a slippery concept 😖



as it would take a few months for the macrocytosis to disappear I don't think the time interval is really long enough. unless it was very marginal in the first place

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Doh...all down to GP's interpretation of 'normal' then...😄


I don't want to hijack again, but if I post my bloods tomorrow could you please interpret them for me? Confused now about macrocytic and megaloblastic! I know it's late, maybe the fog!

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Yep...no problem hijacker Greenbexy. Put them in a new post 👍


Wow thank you all so much for taking the time to read through my post & kindly responding. I've never been on one of these forums before & I really wasn't expecting a reply, so thank you for helping me understand as it's confusing the hell out of me. I'll have a read through the links you posted too, thank you. I'm based in the U.K. & the b12 I've been taking is 1000mg & I have felt a bit better since taking them. I didn't know you could request a copy of your blood results so I will do this too. You've been so helpful, thank you.

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1000 mcg could make a difference even if you had impaired absorption. definitely enough to start raising levels if you didn't have an absorption problem

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Can drinking alcohol affect b12 absorption? I drank a lot more over Christmas & new year but stopped after New Year's Eve. For the first few weeks after I was getting horrible panic attacks, heart palpitations & waking up in the night gasping for air as I couldn't breathe. When reading I also had a kind of brain fog (I've had this a few years now) it feels like my brain is being squeezed in a vice & when it happens I find it hard to take in what I'm reading & I really have to concentrate & focus to take it in. I've not touched any alcohol since as i'm scared it'll happen again but the symptoms have improved.

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Only come across anecdotal evidence on alcohol and B12 - I certainly notice that I seem to run out of B12 quicker if I'm drinking - not a big or frequent drinker.

B12 is stored in the liver and alcohol can affect the liver but that is unlikely to be a part of what is going on if you are being treated for a B12 deficiency - but may be that it is interacting with processes that B12 is being used for.


Hi dobbins,

The description of all your symptoms, especially about reading, is exactly what has been happening to me over the past 2 years. Used to read intellectually demanding books (and some light hearted ones too for relaxation!) but had to stop reading these books feeling my brain was being squeezed in a vice as you have so aptly described and it makes it very hard to understand what has been read, feeling very tired and had to abandon my reading. I found that so very scary and wonder whether my brain has started to shrink... ??? Even after much "forced" concentration and extra focus it has become difficult to take it in....

Like you, and many others no doubt, I have given up drinking alcohol (not that I drunk a lot) since September last year. I Have not had any B12 treatment yet (starting next Monday) and wonder whether I'll be able to take in again what I read once treatment has started.

If I understand correctly you have started your treatment and you found an improvement regarding reading and comprehension?

Your blood tests showed you had a low B12 level, and that you have large bloods cells with a lower uptake of haemoglobin. Unfortunately my B12 level was not what a GP or guidelines would call "low" but there is an overproduction of read blood cells, which my GP has still been unable to explain, except "it's normal for me with my health issues").... and both MCV and MCHL are below range. Did the lab noted a comment about large red blood cells (or did it just say RBCs over range?) OR was it your GP who interpreted the results, ie: stating large RBCs? The reason I am interested to know is because my GP has "ignored" the lab notification regarding the overproduction of my RBCs.

It is so very difficult for all of us in getting the help we need from GPs... and consultants... it should not be.

Wishing you well.


Hello JGBH, sorry you are suffering too, I was wondering if I had permanent damage to my brain too, when reading I struggle with words I never used to struggle with and really struggle to find the words I want to use during conversations. I've felt like I've been losing my mind. I tried to learn to drive for 3 years having 4-6 hours a week and I just couldn't grasp it, my short term memory is awful and I would forget what I had been told during lessons and in between lessons. In the end my instructor told me to give up and said I wouldn't ever pass & I'm wondering now if B12 had some effect of me learning new skills. It's so frustrating, especially when my family say it's because i'm not trying hard enough. During my lessons I would just zone out for a few seconds and lose concentration & my brain would just get tired so it's probably safer for everyone that I'm not on the road but it does hold me back in life. I haven't started injections as I moved house & I was using taxi's to get to my old Doctors so it would have been really expensive travelling there and back to get them. I asked if I could change doctors and have my treatment there, they agreed as long as I had them done. In the mean time I have been treating myself with 1000 mcg of vitamin 12 supplements which I have found have helped a bit. The new Doctors have advised me to wait 3 months from the first result before having it tested again and said that I do not need injections. She said although my B12 is low my blood count is normal which confused me and is why I searched online & posted here. My first Dr said I had enlarged blood cells so I'm really confused as I've not seen my results but now I know I can request a copy I might do this. I don't know if anything has been notified by the lab or if it's the Dr's interpretation, sorry. Good luck with your treatment next Monday, let me know how you get on. I hope things improve for you, It's nice to talk to people going through the same thing :) Regards, Debbie.

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Hi Debbie,

Thank you for your reply. It does help psychologically to be in touch with people going through same or similar problems, although we don't know whether we'll get real help and improvement with an appropriate treatment, hence we worry on top of feeling so ill.

Like you (and maybe many other on this Forum?) I go through very hard times when I think I am losing my mind..... difficult to literally take things in, which was never a problem before... not being able to actually understand some explanation (again this was not the case in the past), all this is most scary and makes one feel so vulnerable and isolated. For example I find it very difficult to use my computer properly, and this is not due simply to the fact I am a bit of a technophobe, but more so that I find the tasks difficult to grasp sometimes. It is so frustrating and it makes one feel rather stupid, just as you must have felt, perhaps, about learning to drive. It is difficult for people around you to truly understand what you are going through... indeed they think you are not making enough effort... which is not the case and is adding to the stress and anxiety we feel.

You are legally entitled to have copies of ll your tests results. So always ask for them, and don't let a GP tell you you can't. You'll be very surprised to see GPs always tell you everything is "normal"..... when in fact it often is not the case.

Do hope you will be getting your treatment very soon and that maybe you'll recover some skills and regain some peace of mind and confidence.

Take good care.


Sorry, the other thing I suffer really bad with and have done since about 21 is acne. I've been on Roaccutane, antibiotics, the pill and tried lots of topical treatments & nothing has cleared it. I always thought B12 triggered acne breakouts. Does anyone know if a B12 deficiency can cause acne or can the injections make it worse?


B12 can lead to acne - probably not a direct reaction to the B12 but a by product of the way the micro-organisms on your skin react to B12 - by excreting a toxin that can irritate the skin.

Having B12 after a period of deficiency does seem to send the immune system slightly into overdrive so it may just be a temporary affect and calm down. Suggest you talk to GP/pharmacist about medication for the acne - particularly if it doesn't seem to calm down.


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