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Pernicious Anaemia Society
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Injections v sublingual spray

I need some advice please. Just over a year ago I was feeling very unwell and had been for some time. I was very tired, emotional, pins and needles and numbness in my feet, painful scalp and hair loss, strange taste in mouth, IBS and many other symptoms. Doctor took bloods and I was diagnosed with low B12 (150) and low D. I was never tested to see why I had become deficient? Had weekly jabs for three months then moved to monthly. My bloods were tested twice more during the year and my levels were around 300-400. Last November a new nurse decided to take me off the injections and try me on B12 tablets for three months. I was already overdue an injection and feeling awful but they insisted that this was route to take. After a week of the tablets I had such terrible stomach ache that I stopped taking them. I purchased a B12 spray instead and felt a bit better generally. I then went for the next blood test and my levels are now 850??!! I'm feeling so tired and the numbness is back in my feet. Last injection was last August and I have a review appt next week at the docs. I know they will look at my levels and say that I'm now fine but I know I'm not! Will the B12 spray have skewed my blood results this much? If my blood levels are 850 am I now ok and are my symptoms maybe due to something else? I'm so confused with all this and don't know how to approach my doctor next week. Any advice will be gratefully received....

13 Replies

Are you in UK?

Sources of B12 info

1) PAS (Pernicious Anaemia Society)

PAS tel no +44 (0)1656 769 717 office open from 8am till 2pm every day except Sundays and some holidays.



2) B12 Deficiency Info website


3) b12d.org website


4) Book "What You Need to Know About Pernicious Anaemia and Vitamin B12 Deficiency" by Martyn Hooper. Martyn is the chair of the PAS. the book is up to date with current UK B12 guidelines.

5) Book "Could it Be B12" by Sally Pacholok and JJ. Stuart

6) Pinned posts on this forum

I found the summary fbirder compiled helpful to read. link to summary in third pinned post (last link in list)

7) BMJ B12 article


8) BNF (British National Formulary)


9) BSH Cobalamin and Folate Guidelines. These UK guidelines came out in 2014. They give recommendations on the treatment and diagnosis of b12 deficiency/PA.

b-s-h.org.uk/guidelines/ click on box that says "Diagnosis of B12 and Folate Deficiency" should be on page 3 or put "cobalamin and folate guidelines" in search box.

Link to a flowchart in BSH Cobalamin Guidelines which shows when IFA (Intrinsic factor antibody) test should be ordered. IFA test can help to diagnose PA but is not always reliable. It is possible to have PA with a negative result in IFA test.


I am not a medic just someone who has spent years trying to find answers.

Unhappy with treatment?



HDA patient care trust

A Uk charity that offers free second opinions on medicla diagnoses and treatment.


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Yes I'm in the UK.

Thank you very much for your detailed response. I will take a look at your links...

Many thanks again


Hi Becs67 Have you been supplementing with folic acid during this time and was your low Vitamin D treated as "cause and symptoms" of deficiency are somewhat similar?

Some on here will say that only about 2% of B12 Spray will be absorbed but because of the "high dose" sufficient will get through for a "maintenance" RDA.

I'm not a medically trained person but do use the spray between injections and have supplemented with 400mcg folic acid every day for more years than I can remember.

I hope you get back onto injections soon and wish you well.

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Thanks for your reply.

Yes I have been taking D supplements but haven't taken Folic Acid...was never mentioned by my doctor?

Will ask about this at my review.

With thanks

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Do you get copies of all your blood test results? In relation to b12, I look at serum B12, folate, ferritin and full blood count (FBC). I learnt to get copies of all blood tests after being told everything was normal/fine face to face and over the phone and then finding abnormal results on the copies.



"I was never tested to see why I had become deficient?"

Have you ever had an IFA test?

This can help to diagnose PA but the test is not always reliable, it is possible to have PA even if IFA test comes back negative. Antibody Negative PA is mentioned on the flowchart I gave a link to, in post above.

My understanding of the BSH flowchart (I'm not a medic) is that people with low b12 and those who have a within range B12 result but are symptomatic for B12 deficiency, should be given an IFA test.

Has your GP explained why you have not had an IFA test?

If you get copies of all your blood test results and look at the result for B12 when it was 150 it's possible that the laboratory that did the test may have included a note suggesting an IFA test.

There is at least one person on this forum who found out they had been diagnosed with PA in the past but not told at teh time. some people get a whole set of their medical records. some surgeries have online access to a summary record but this does not necessarily have all medical info.


If you are vegetarian or vegan the GP may think that the low B12 is diet related. Its possible to have more than one cause of b12 deficiency at the same time.

Coeliac disease

Have you ever had a test for Coeliac disease? People can have Coeliac disease even if tests for Coeliac antibodies is negative. I think Coeliac disease can lead to IBS type symptoms.


Causes of b12 deficiency


"a new nurse decided to take me off the injections and try me on B12 tablets for three months"

I would suggest talking to the PAS soon. Contact details in my post above. They have experience of talking to people about injections being stopped.

"pins and needles and numbness in my feet"

Untreated or inadequately treated B12 deficiency can lead to permanent neurological damage including sub acute combined degeneration of teh spinal cord.

There is a medical section on PAS website for medical professionals that Gps might find useful.


I gave my GPs a copy of Martyn Hooper's book and a copy of BSH Cobalamin and Folate guidelines.

Family link PA

Do you have any blood relatives with PA or b12 deficiency or other auto-imune conditions?



Ok thanks...will go to the surgery later and ask for copies


There is likely to be a small charge per copy eg 50p plus.

As far as I know the only reason to refuse a request for copies is if GP feels it would cause a patient harm in some way.

The GP will need to approve the request so it may take a few days to get copies.


When I was first told that I was B12 deficient the doctor said that I will prob have to have injections for life and they said that they would test for IFA. Then when the bloods came back the hospital had decided not to test because I'd just had my loading injections and my levels were 300! They said that this was in normal range so no need to test! So frustrating. The doctor then forgot to add to the next blood tests because wrongly assumed I was Vegan...which I'm not and eat healthily in my view.

I will bring this up at my next review again. Thank you

I don't know if any relatives that have PA and not sure about Coeliac disease. I haven't been tested for this either. I will raise this as well.

I'm just worried that they will send me on my way as my levels have now shot up to 850! We will see..!

You've been very helpful...thank you


I think it's possible that neither the GP or hospital lab are aware of the BSH Cobalamin and Folate Guidelines. I gave a copy of BSH guidelines to my GPs to make sure they were aware of it.

As I said above the BSH Cobalamin and Folate guidelines flowchart appears to show that people who are low in b12 and those who are within range but symptomatic shoudl have an IFA test.


"because wrongly assumed I was Vegan...which I'm not "

Have you put it in writing that you are not vegan? Gps may forget some of what is said in a consultation. I wrote in one letter that I ate fish, dairy, meat ...all good sources of B12...so GPs would not assume low b12 was due to diet.

What I did find out was that some local NHS areas in the UK have their own B12 deficiency guidelines. Some of these local B12 guidelines have not been updated since the BSH Cobalamin and Folate Guidelines came out in 2014. It's possible that Gps in your area are following loacl NHS guidelines.

These local NHS guidelines may be found by an internet search, a search on local NHS website, a FOI (Freedom of Information) request to local NHS website, request to local CCG nhs.uk/ServiceDirectories/P... MP may be able to help.

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once you have started treatment then the levels in your blood aren't a useful guide any more - though it is unfortunate that this often isn't recognised.

How long after your loading doses/maintenance shots was the blood result that came out at 300/400 - to be honest this sounds low for someone who has recently had a B12 shot and indicates that you are not retaining B12 very well ... though retaining it in your blood doesn't necessarily mean you are okay - as you know.

PA is not the only absorption problem that will lead to a B12 deficiency and even if it were the IFA test isn't very reliable and is prone to false negatives - ie saying you don't have PA when actually do - this can happen 40% to 60% of the time depending on the exact assay method - so a negative result would not rule out PA.

You need to leave it at least a week between a B12 shot and an IFA test as the shot can produce false positives.

So, negative IFA doesn't prove that you don't have PA.

Even if you don't have PA you could have another absorption problem .... and if the cause of the B12 deficiency is an absorption problem then the treatment will be injections for life. The NICE guidelines are rather ambiguous when it comes to IFA/PA and treatment and could do with being a lot clearer that tablets are okay if the problem is definitely dietary but if this isn't the case then it will be B12 shots.

It would be useful to know what the strength of the tablets you were prescribed was - probabaly 50mcg cyanocobalamin - which would never be enough if you have an absorption problem. No other tablets are currently licensed for treating B12 in the UK.

Really hope you can get through to the GP and get the treatment you actually need

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Hi...thanks for your response. The 300/400 blood test results were two months after the injections. Remained constant for the year like that. It's only just shot up to 850 on the last test because I've been taking the spray I assume? The tablets that the doc wanted me to stop the injections for were the 50 mcg as you stated. I am sure that they are going to now say that my levels are fine! Should never have tried the spray but was feeling rubbish so not much choice!

I'm personally sure that's it's an absorption problem of some kind as I struggle with an uncomfortable bloated stomach a lot of the time so sure something's not quite right! Could food intolerances result in absorbtion problems do you know?

Sure doctor thinks I'm just a pain sometimes!

Thanks for your help....


I have PA and had stomach issues especially bloating and sometimes tummy ache . A gastroenterologist told me that PA patients have low or no stomach acid (Hypochlorhydria or Achlorhydria ) no NHS treatment for it . I found that a good probiotic helped to normalise my stomach flora which had been upset due to lack of Hydrochloric acid . I suggest a good probiotic for your bloating . There is a wide choice . You can make your own with fermented organic cabbage (sauerkraut !) Best wishes


Thank you for your reply.

What probiotic do you recommend please?


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