I think I read here that you can have a normal serum B12 result but be deficient if the B12 is not getting through to the cells. I have always received copies of my blood test results so I know that in theory I am definitely not deficient as my last test in October 2021 was 698 (197-771) but I feel as though I have some of the symptoms. I’ve had fatigue and weakness for around 5 years and also suffer from heart palpitations. These have been checked out and I have had a heart scan which showed nothing sinister. My MCV is always higher than normal; it was 100.7 (80-99) in April last year. I don’t know if that is high enough to be classed as macrocytic anaemia.
I did have a folate deficiency two or three years ago but was treated with high dose folic acid for 3 months and I now take a 400mcg tablet per day. I also use a B12 spray every day to no avail.
I have a telephone appointment booked with my doctor next week and just wondered if, with the above symptoms, there could be a possibility that I have a functional B12 deficiency. I know from posts I have read here that doctors don’t seem to know an awful lot about B12 and certainly don’t like patients suggesting their own diagnosis but does anyone know of any additional tests I could ask for that might help me get to the bottom of why I feel so weak and exhausted. I would be very grateful for some advice. Thank you very much.
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I dont know where you are based, but a schilling test will be able to distinguish between active and inactive b12. This test is not available in the uk although I have heard of one person to get it here. It is much more accurate.
If you get tested while taking supplements, they can affect the result. If I inject with b12 today it will show a large amount of b12 if tested - it doesnt mean im symptomless.
Have you had a pernicious anemia test? It is worth repeating, sometimes can take a few goes before a positive result.
B12 deficiency should not be treated based on b12 levels in blood but on symptoms. I have been diagnosed with PA so I cannot be refused treatment, this is a life long condition for me. I will not be looking at my b12 blood levels, i will inject every month and monitor whether it is enough.
In the uk we inject hydroxocobalamin, which some have indicated stays in the system for longer. I certainly have heard that some people have to try different sources of b12 to find what works.
Answering your question directly, you can have a b12 deficiency with associated symptoms while having large amounts of b12 in blood. B12 deficiency is not a blood disorder, it is a gastro issue.
You have other related symptols with the low ferritin etc
Did the gp give you the b12 spray or is that something you tried?
Pernicious anemia can be very serious if untreated.
If your dr is dismissive of you, then go elsewhere.
I had to be much more proactive - my gp stopped the injections completely due to a b12 reading but after 6 months i was in hell with it. I got in touch with the PA society and this forum, then went back to my medical practice with the correct info and nhs guidelines etc They reviewed their b12/pa treatment and changed according to guidelines. They were really great about it and there was no awkwardness about it.
Thank you for replying. I'm based in the UK. No, the GP didn't give me the B12 spray I bought it from Amazon in the hope it might help but it doesn't. Can I just ask, if I did have pernicious anemia wouldn't my B12 be lower than 698?
The other thing that occurred to me was that I did have my gall bladder removed 20 years ago, but is that the sort of surgery that can stop someone from absorbing B12?
My ferritin levels are actually fine.
Thank you again for taking the time to reply, it is much appreciated.
I initially had an MMA test done and my then private endocrinologist said I had functional b12 deficiency, I then arranged an Intrinsic Factor test which came back positive for Pernicious Anemia so I assume I have both as I need to self inject more frequently than guidelines,I was every other day but have now managed to reduce that to weekly which I seem to do ok with.Best of luck x
Thank you very much. I'm going to ask the GP to do the tests and if he refuses I will pay to have them privately as I'm now at the end of my tether.I'm happy for you that you have been able to reduce your injections. I hope your health continues to improve.
Links to forum threads where I left detailed replies with lots of B12 deficiency info eg causes and symptoms, UK B12 documents, more B12 books, B12 websites and B12 articles and a few hints on dealing with unhelpful GPs.
Some links may have details that could be upsetting.
My last folate result was 7.5 ug/L (2.4 -20.00) so that looks OK I think. Thank you so much for all the information. I feel well armed now to fight my corner and know what to ask for in terms of blood tests.
If GP won't order the tests you think you need, they should be available from private health sector in UK.
NHS is unlikely to accept private results but a private test that shows a significant result should be enough to nudge NHS GP into ordering the same test or referring you to a specialist who can order the test.
UK B12 documents
NHS article about B12 deficiency and folate deficiency(simply written, lacks detail in my opinion)
If you click on "project documents" then on "consultation comments and responses" it gives a good insight into current issues around diagnosis and treatment (over 40 pages).
See Cautions section in above link which says that folic acid should never be given on its own for PA (Pernicious Anaemia) or other megaloblastic anaemias caused by Vit B12 deficiency as this may lead to SACD, subacute combined degeneration of the spinal cord.
Each CCG (Clinical Commissioning Board/Health Board/NHS hospital trust in UK is likely to have its own local guidelines on treatment/diagnosis of B12 deficiency and may have separate guidelines for folate deficiency. Might be worth tracking down the local guidelines for your area of UK and comparing the info in them with BNF, BSH and NICE CKS links.
Some local guidelines have been posted on forum so try a search of forum posts using terms "local guidelines" or try an internet search using "name of CCG/Health Board B12 deficiency guidelines" or submit a FOI (Freedom of Information) request to CCG/Health board asking for access to or a copy of local B12 deficiency guidelines.
I think I'm a bit of a complicated case as I've had blood letting in the past for high ferritin levels and two different types of cancer.
I hope I'm not clutching at straws by thinking it's functional B12 deficiency. I suppose there could be a number of illnesses which can leave you with weakness and fatigue and when you reach my age (coming up for 70) I think GPs think it's par for the course and don't really care. The last doctor I saw about the fatigue, told me not to drink coffee!
Anyway, thank you very much for taking the trouble to send me all the links. I'm working my way through them and I'm not going to be fobbed off by my GP this time!!
"when you reach my age (coming up for 70) I think GPs think it's par for the course "
I agree with that comment.
There was a thread a while ago where several forum members including myself expressed a wish that we'd known more about B12 deficiency years ago so we could have helped our elderly relatives avoid dementia and other health issues relating to B12 deficiency.
"I hope I'm not clutching at straws by thinking it's functional B12 deficiency."
I don't think you re clutching at straws, more being your own medical detective.
It can be hard if you're younger as well.
I was given a label of ME/CFS/Fibromyalgia/depression/hypochondria etc when my body was crying out for B12.
Have you considered writing a letter to GP expressing your concerns?
I always suggest putting concerns over treatment/diagnosis into a brief, polite letter to GP. Useful to have a paper trail in case there is a need for a formal complaint in future. Always keep copies of letters sent/received.
UK guidelines on B12 deficiency indicate that patients with the symptoms of B12 deficiency should be treated even if serum (total) B12 is within range.
See BSH summary link in my other reply.
Are your symptoms consistent with B12 deficiency?
Symptoms of B12 Deficiency (folate deficiency also mentioned)
I think the idea of writing a polite letter is a really good one! I'll wait to see how I get on with the telephone consultation next week and if the GP doesn't agree to the blood tests you suggested, I will definitely write a letter of complaint.
I really appreciate the time you have taken to send me all the information and I'll let you know the outcome.
I do hope your GP will speak to the specialists whose care you were under before.
The blood tests I mentioned eg MMA, Homocysteine, Active B12 are expensive and there are financial constraints on GP practices in UK so you may find they are reluctant to order them.
Make sure your GP/specialist knows that you are supplementing with a B12 spray as they need to consider this when looking at your test results.
You could try to get hold of local guidelines for B12 deficiency in your area of UK and to see if there is any mention of functional B12 deficiency in them.
If you write a letter to GP, may be worth including extracts from UK guidelines that supports what you have said. See links to UK B12 documents in my other reply. Worth including a list of any symptoms that are suggestive of B12 deficiency.
GPs can find it hard to cope with an assertive patient who asks questions so be prepared for GP/patient relationship to come under strain.
Rather than a letter of complaint, maybe think about writing a persuasive letter.
If they say there is no way you could have B12 deficiency, there may be info in next links that could be useful.
The summary of BSH Cobalamin and Folate guidelines includes the statement
"In the presence of discordance between the test result and strong clinical features of deficiency, treatment should not be delayed to avoid neurological impairment"
May be worth looking at link to complete BSH Cobalamin and Folate guidelines in my other reply to see if there is any mention of functional B12 deficiency.
"I've had blood letting in the past for high ferritin levels "
Were you ever checked for a condition called haemachromatosis which can lead to iron building up in tissues?
Once again, thank you so much for all this brilliant information. Both the consultants I was under when I had cancer were aware of my fatigue but didn't seem too worried or didn't order further investigations.
I do have one of the faulty genes that predisposes one to haemachromatosis. Even though I technically don't have it, I've still had a few sessions of venesection and now my transferrin saturation is under 50%. I have an appointment to go again in four months time but if my blood stays under the magic 50% I won't need to have it.
About four years ago I paid to see a private endocrinologist as I'd read an article about a woman with similar symptoms to me, who found out she was deficient in Thyroid T3. Apparently the NHS do not routinely test for this. I had a partial thyroidectomy years ago so was convinced that this was going to be the solution. Unfortunately my results showed my levels were fine (and still are) and that is without having to take any Thyroxine.
I feel more positive now that I'm now armed with so much "ammunition" that you have kindly sent on to me and think I might be able to fight my corner strongly this time and insist on some more blood tests.
Thank you very much for this Sleepybunny. It was a very interesting read, particularly the part about the genes.
I will remind the GP about this as I think it will be even more important to have the MMA test to rule out B12 deficiency as there is the chance that my fatigue could be due to Hemochromatosis.
Might be worth putting reminder in a brief letter to GP as harder for GP to ignore/forget and keep a copy of letter. Maybe send GP a copy of NORD article.
Haemachromatosis UK (UK charity for those with haemachromatosis)
HiI am in a similar position to you, all the symptoms of PA, but serum B12 came back as 737ng/L. Also have a high MCV 98.3. My folate was 5.4 ng/mL, ferritin level 26.3 ug/L. With a bit of googling I found out that even though my ferritin level is within range (13 is the lower limit), a good level is over 70, so I'm supplementing with iron to see if that helps. My GP has just referred me to a chronic fatigue clinic as well, could you ask yours about that perhaps? Frustrating isn't it when everything is within range but you know something isn't right
Thank you very much for your reply. Yes it is very frustrating and it has been going on so long now I really feel I've got to get to the bottom of it. I've been to the GP so many times over the last few years and not once have they even suggested a referral to a chronic fatigue clinic. Mind you they have suggested I'm depressed. I'm not depressed just incredibly fed up with feeling so ill.
Did your GP give you the tests that Sleepbybunny listed in his reply?
I hope your referral to the clinic is of some help.
Mine also mentioned depression, and I said the same that I'm fed up with feeling tired all the time and struggling to do things I could previously. It's tough when it feels like a battle with your GP isn't it
It certainly is! Made even worse when everything seems like such an effort. I expect that's why people take matters into their own hands and self inject.
No, I have a needle phobia and there's no way I could do it myself.I will get the blood tests privately if the GP won't do them and then decide what to do.
And you, really hope you're able to get the tests done. I'm not sure if I could self inject either, sad that people have to do it isn't it, wish there was better knowledge and help out there x
Just thought I'd mention I had a difficult time after being referred to ME/CFS services.
Once I got stuck with a label of ME/CFS/Fibromyalgia, all efforts to try to find out what was wrong with me stopped. While I accept that ME is a real neurological condition, I think many people diagnosed with it have something else.
My understanding is that ME/CFS should not be diagnosed in UK until all other possible causes for symptoms are excluded.
In my part of UK, ME/CFS was treated more as a mental health condition which was incredibly frustrating as I knew there was something physically wrong with me.
I had over 40 typical symptoms of B12 deficiency, including many neurological problems and asked GPs and specialists many times if it could be B12 deficiency. I had had a previous below range serum B12 result but most later B12 results were between 300 - 500 ng/L.
In the end after fighting really hard for several years to get a trial of B12 treatment, I gave up on NHS and resorted to treating myself. Today the majority of my symptoms have gone or greatly improved.
Misdiagnosis of B12 deficiency as ME/CFS and other conditions
That's interesting to hear Sleepybunny, do they not do any further investigations before a diagnosis at the chronic fatigue clinic? It was in October 2020 I first suspected PA, at that point my GP basically told me that as everything was in range to just live with it.... but to come back if it got worse. When I felt worse this year I went back and had the blood tests again, but I haven't been able to get them to carry out any of the tests you mentioned. Were you able to get them done on the NHS? I wonder if I should have them done privately, shame it's so expensive though. I'm going to persevere with the supplements I've started and see if they help first I think
I found there was a lack of interest in finding out if the chronic fatigue was due to any other condition.
As far as I remember I had to ask for most of the referrals to specialists I got.
I used to put referral requests into polite letters to GP along with evidence eg symptoms, extracts from UK documents that supported the request
I had to be very pro-active which is pretty hard when your brain feels like it's full of cotton wool. This did not go down well with GPs...pretty sure they had me down as a trouble maker.
I remember one GP asking me who is behind the tremendous effort to find out what is wrong with you and when I said it was me, he was shocked.
I never understood his shock, why would someone who was ill not try to find out what was wrong with them especially if GPs were unhelpful?
The previous NICE guidelines on ME/CFS said something about not testing B12 levels routinely so hopefully the updated NICE ME/CFS guidelines are better.
I was able to get some of the tests on NHS but via referral to a specialist.
My experience was that there are specialists whose understanding of B12 deficiency is lacking.
I think my ME/CFS diagnosis prevented me finding out what was wrong for a long time as GPs felt they had ticked the right box for me.
If you get tests like Active B12, Homocysteine, MMA privately bear in mind that NHS may not accept the results but something significant in results may be enough to prod them into ordering the same tests.
The results of the three tests above may be affected by recent B12 injections/supplements so make sure whoever is testing knows about any B12 supplements you are on.
That's really useful thanks. Funnily enough the time the GP told me I just need to live with it was when I put together a load of information and asked for specific tests. It's a shame that some react so badly to a patient being proactive and trying to help themselves isn't it
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