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Pernicious Anaemia Society
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Newcomer - B12 Deficiency Advice Please

Hi All, I'm new to here having ended up here through a worry more recently about a B12 deficiency. Just to give you a bit of info, I'm 26 average fit and healthy woman, eat a good balanced diet but do have IBS. I've suffered with chronic fatigue for a long while now which I'm really struggling with lately; constantly feeling like I could just close my eyes and go to sleep, no energy, feeling weak and unsteady. The past 6-9 months I've been getting increasingly more pins and needles and numbness in my arms and legs which had me really concerned. My Mum has MS so my initial worry was that I too had symptoms (I know it's not hereditary but my risk is increased due to genes from what I understand), though I think it's more I'm just over-thinking things. My vision seems to be deteriorating too and ocassionally get pain on eye movement. I've been feeling faint quite often, have a lot of aches in my hips, legs, arms and back. To say I'm fed up is an understatement! I feel like a hypochondriac and I'm of the disposition that I usually go strictly on advice of the doctor, i.e. if he says everything is "normal" then I go along with it. Now I've reached a point where I've just had enough and want to get to the bottom of this constant tiredness. I have been taking supplements for over a year now, almost daily and I take the following:

Vitamin C 500mg

B12 1000ug

Vitamin B complex

Vitamin D3 25ug (stopped taking when it reached the summer)

When I last saw my GP I raised my concerns about my B12 deficiency and about MS too. He did some reflex tests on me; my arms had great reflexes but I had no reflex in one knee at all and almost absent in the other knee, he frowned at this and said it was odd but nothing else. I stopped taking all my supplements for about 12 days before my latest blood test to be sure that they would be accurate. My results were as follows (apologies, I don't know what they all mean so I've listed the majority);

Serum B12 304 ng/l

Serum folate 6.8 ug/l

Serum TSH level 1.95 mu/l

Serum Ferritin 102 ug/l

I had full blood count as well - if it helps to give you these please let me know. Basically everything came back as normal according to the GP. I got copies of all my blood tests from the past 12 months having been down the route of trying to find what was causing the tiredness. Previous Blood results were:

Jul 2015;

Serum B12 237 ng/l

Serum Folate 12 ug/l

Serum TSH level 2.89 mu/l

Dec 2015;

Serum B12 244 ng/l

Serum folate 10.5 ug/l

I had a test in August last year to check for parietal cell antibodies and it came back negative. From what I understand this means I don't have pernicious anaemia?

Sorry for the long essay on this post! I'm grateful for any advice you can give me, if you think this still could be a B12 deficiency and how best to approach my GP in a few weeks time when I next see him. I'd like to at least try an injection to see if it helps seeing as I've continuously taken the supplements and I don't believe they've helped at all. Thank you in advance for all your advice, I really am grateful and will now continue spending time reading posts on here. Thanks

18 Replies

I also meant to add that I've been having some confusion and a lot of the time have a total lack of concentration. I put it down to just feeling tired but I worry these could be symptoms too? Thanks.


Hello 2torts and welcome to the forum.

Interpreting results as figures in isolation is always a bit difficult but made a bit more so by lack of ranges - tests generally come with a range that provides a guidance as to what would be deemed statistically normal - important because different machines used to measure can have different ranges. However, your folate is on the low side and so is your B12.

Another difficult thing about interpretting results is that with some - and B12 serum is one - people respond very differently so the statistically normal range isn't necessarily a good guide as to what is going on with an individual - so symptoms become much more important. However, even then B12 isn't necessarily clear cut because of the overlap between symptoms of B12 and a number of other conditions ... and many of the conditions can actually occur together so there could be more than one thing going on.

I really can't comment on your TSH level which is a measure of thyroid but people on the TUK forum and there a number of crossovers because its common to have thyroid and B12 problems at the same time - may come along and be able to advise on that.

It would be useful to have the full blood count as that will give some indication as to whether there is any evidence of macrocytosis - enlarged deformed blood cells which are a very common sign of a B12 deficiency - but not always present.

Is your GP following up on the abnormal knee response at all - eg with a neurology referal?

Please take a look through the pinned posts - there are a lot o materials there which would help you understand more and which might help your GP understand B12 deficiency a bit more and explore that as a possibility with you.

Generally B12 deficiency isn't dietary but its caused by an absorption problem - which means that taking tablets is not a very efficient way of trying to get additional B12 if you have an absorption problem - it works for some but there are many that it doesn't work for.

It would also be useful to know precisely what form of B12 you are supplementing with - probably methylcobalamin - and again that works well for some people but doesn't work for eveyrone


Hi Gambit, thank you for your informative post, that's a big help. Sorry I should have provided the ranges. Here are my results with the ranges:

Latest Blood Test:

Serum B12 304 ng/L (197-771)

Serum Folate 6.8 ug/L (4.6-18.7)

Serum TSH 1.95 mu/L (0.27-4.2)

Serum Ferritin 102 ug/L (13-150)

Haemoglobin estimation 137 g/L (115-160)

Total white cell count 5.7 (4.00-10.50)

Platelet count 243 (145-400)

Mean corpuscular volume 89.5 fL (80.0-101.0)

Haematocrit 0.414 (0.36-0.46)

Red blood cell count 4.62 (4.00-5.20)

Mean corpusc. haemoglobin 29.7 pg (27.0-35.0)

Mean corpusc. Hb. Conc. 331 g/L (310-360)

Neutrophil count 3.05 (1.80-7.50)

Lymphocyte count 2.12 (1.30-4.00)

Monocyte count 0.48 (0.20-0.80)

Eosinophil count 0.06 (0.02-0.40)

Basophil count 0.03 (0.00-0.20)

Report reads: Normal

The ranges for my previous blood tests as in my original post are the same as these above (in brackets). My blood test in Dec 2015 showed my neutrophil levels were below and notes say "borderline neutropaenia" yet my GP told me everything was normal, so just makes me question why we have the ranges in the first place?! My B12 readings have gone from 237 to 244 to 304 in the last 12 months, so possibly the oral supplements I take do make a difference but only very marginally. My folate levels have done the opposite though; they have gone from 12 to 10.5 to 6.8 in the past 12 months. I was under a gastroenterologist about six years ago when going through endless tests (before being diagnosed with IBS) that my folate levels had come back low and was told to take folic acid supplements which I took for about 6 months.

At the moment my GP isn't following up with anything based on my reflexes, saying he wants to rule out a B12 deficiency first. He's a fantastic doctor and the first I've found where I feel he's sympathetic to a certain degree and will do more investigation. He did however say it takes on average 14 years to get a diagnosis for a B12 deficiency, he had better be joking!! I'm due to see him again in a couple of weeks' time and will be discussing my results and what he wants to do next. I won't be leaving without some sort of further investigation or hope to ask for a trial of the B12 injection to see whether it improves my symptoms. My lack of concentration is worrying at the moment to which it is really affecting me at work. I find myself forgetting things occasionally too and on top of the tiredness I just feel like my symptoms are worsening and I'm really struggling.

I'll keep you all updated and once again, thank you so much Gambit and everyone else for your advice. It's nice to have someone to talk to about it and I'm finding the information online very helpful - I just wish GPs could take time to read it all too.

The supplements I'm taking are as follows:

Tesco branded B-complex (been taking for 9 months);

B1 1.1 mg

B2 1.4 mg

Niacin 16 mg

B6 1.4 mg

Folic acid 200 ug

B12 2.5 ug

Biotin 50 ug

Pantothenic Acid 6 mg

Tesco branded slow release vitamin C (I suffer from tonsillitis and throat infections frequently so thought this would help, been taking for 8 months);

Vitamin C 500 mg

Holland & Barrett (on the GP's advice) B12 (for 12 months):

B12 (as cyanocobalamin) 1000 ug

Thank you again for all your help.


If you are taking 1000mcg tablets of cyanocobalamin would expect your levels to be much higher than they are if you don't have an absorption problem. Are these tablets that you swallow or are they ones that you disolve under your tongue. They may be maintaining your B12 levels but they certainly aren't doing any more than that.

Most B12 is absorbed in the ileum but about 1% is absorbed 'passively' outside the ileum so 1000mcg is about 400 x RDA for someone who doesn't have an absorption problem so you will be getting a few times RDA - which might be enough to just keep your levels stable

As fbirder says the variation in your results isn't significant enough to be able to draw any conclusions, beyond that the levels seem about steady.

The trend with folate is a bit worrying as you can't use and process B12 without folate so it could be a contributing factor - one possibility is that you are processing slightly more B12 because of the oral supplementation but its having a knock-on effect by slowly depleting your folate levels.

Think the materials fbirder provided will cover the fact that going purely on test results for B12 is wrong - the normal ranges are about statistical averages but there is so much individual variation in normal responses to B12 that they are particularly misleading with B12. It sounds like your GP is one that isn't actually falling into the trap of going just by results if they are determined to look into B12 and is on top of going by symptoms.

The fact that a blood test may throw up an anomalous reading isn't necessarily cause for concern - because there may be a number of things that could throw that reading out ... and many of them may not be anything to worry about ... but a combination of figures being out is likely to be much more sophisticated. Alternatively it might be a confirmation of something that is already known - eg neutropaenia is a sign of infections and you mention that you have a tendency towards tonsillitis and throat infections. If you are concerned that a figure was out but your GP doesn't seem to have picked it up then I would raise that with them and ask them why they don't think it is significant.

I had a tendency towards throat infections before I was diagnosed with B12 - found that probiotic honey really helped.

I'm not sure if the average time to diagnose B12 deficiency is still 14 years but it wouldn't surprise me. However, you are working with a GP who is trying to follow up and appears very sympathetic and seems to be coming to the conclusion already that B12 is involved in some way so don't think yours is going to take 14 years.

Guidelines on B12 deficiency tend to focus on bloods and referral to haemo - however, B12 deficency isn't about the amount of B12 in your blood - it is about what is going on at the cell level - and that can affect several systems - psychiatric symptoms, neurological symptoms etc and these can occur well before any sign macrocytosis or megaloblastic anaemia. Personally I'm not convinced by the focus on referals to haemo as I think that plays into the tendency to assume that it is all about anaemia and the amounts of B12 in your blood (I'm not a medic just going on logic here). No guarantee that a neuro is going to be any more aware of B12 though. Going for a trial of B12 sounds like a sensible way to go - and think it would be in accordance with the BCSH guidelines - certainly chimes with a recent BMJ article ... but you also need to keep an eye (with your GP) on folate levels.

Hope that the pinned posts and the reading suggestions from clivealive help you understand a bit more ... and that you can continue to work with your current GP.


I would ask your doctor to check your FT4 and FT3. My TSH was a similar level to yours and I had a fair few of your symptoms, but my FT4 was below range and my FT3 only just in range. A few tests later and I was found to have secondary hypothyroidism. You can't rule this out with just the TSH test.


Hi 2torts I am not a medically qualified person but am interested as to why your B12 and Folate levels are a bit on the low side despite your having taken supplements and stopping only 12 days for the serum B12 is probably not long enough.

On page 23 in the book “Could it be B12? – an epidemic of misdiagnoses” by Sally M. Pacholok R.N., B.S.N. & Jeffrey J. Stuart, D.O. there is a list showing:-

Who’s at greatest risk for B12 Deficiency?

"Anyone at any age, can become B12 deficient. Thus you need to be tested immediately if you develop the symptoms described in this chapter. However, certain people are at an elevated risk. They include the following:

Vegetarians, vegans and people eating macrobiotic diets.

People aged sixty and over

People who’ve undergone any gastric and/or intestinal surgery, including bariatric surgery for weight loss purposes (Gastric bypass).

People who regularly use proton-pump- inhibitors. H2 blockers, antacids, Metformin, and related diabetes drugs, or other medications that can interfere with B12 absorption.

People who undergo surgeries or dental procedures involving nitrous oxide, or who use the drug recreationally.

People with a history of eating disorders (anorexia or bulimia).

People with a history of alcoholism.

People with a family history of pernicious anaemia.

People diagnosed with anaemia (including iron deficiency anaemia, sickle cell anaemia and thalassaemia).

People with Crohn’s disease, irritable bowel syndrome, gluten enteropathy (celiac disease), or any other disease that cause malabsorption of nutrients.

People with autoimmune disorders (especially thyroid disorders such as Hashimoto’s thyroiditis and Grave’s disease) Type 1 diabetes, vitiligo, lupus, Addison’s disease, ulcerative colitis, infertility, acquired agammaglobulinemia, or a family history of these disorders.

Women with a history of infertility or multiple miscarriages.

Infants born to and/or breast fed by women who are symptomatic or are at risk for B12 deficiency.


I see you say you have a good balanced diet but you can "identify" yourself from the list with the IBS and maybe one or two others like medications that affect absorption of B12 - the contraceptive pill for instance.

Some of your symptoms are similar to those of B12 deficiency and if you could make a list of them, present this to your doctor and ask for a trial run of B12 injections to see if there is any improvement he/she may be agreeable.

You could also refer to:

Treatment of cobalamin deficiency

"Current clinical practice within the U.K is to treat cobalamin deficiency with hydroxocobalamin in the intramuscular form outlined in the British National Formulary, BNF,

Standard initial therapy for patients without neurological involvement is 1000 μg intramuscularly (i.m.) three times a week for two weeks.

The BNF advises that for Pernicious anaemia and other macrocytic anaemias patients presenting with neurological symptoms should receive 1000 μg i.m. on alternative days until there is no further improvement."

I wish you well

for the future


Hi Clivealive, how long should you stop taking B12 supplements before a blood test? I had hoped 12 days would be enough, but that might not be the case?

Thank you for the book excerpts, I'll definitely be looking into that book. I can certainly relate with a lot of the symptoms. In terms of IBS, I was diagnosed six years ago after a multitude of tests; barium swallow x-rays, hydrogen breath test (which revealed I'm lactose intolerant - I have been having lactofree milk and cheese for 6 years, other than that I don't cut out completely as it's quite difficult, rather I just avoid where possible like cream, rich and creamy foods etc.), endoscopy, colonoscopy. Diagnosed with IBS after nothing else highlighted. I manage it quite well most of the time but do get bad 'flare-ups' and wonder then what this does to my ability to absorb things like B12? It's something I'd like to look into. I am also on the contraceptive pill and have been for nine years - I didn't know that this can affect the absorption of B12. I take Fexofenadine Hydrochloride, nasal spray and eye drops during the summer months for severe hay fever, other than that I'm on no regular medication.

Thank you again for all your advice, it's a big help to me and I will be carrying out a lot more research before I see my GP again in a couple of weeks' time so that I can hopefully go in there on a mission to get a B12 injection to see if they improve my symptoms.

Thank you again!


As I said at the beginning 2torts I'm not medically qualified but my logic is that if the B12 Hydroxocobalamin is supposed to be "good" for two or three months between injections the at least eight to twelve weeks should be allowed to elapse before a serum B12 test is taken.

However I'm sure fbirder will be happy to give more qualified advice.

Another interesting extract on page 11 in the book "Could it be B12? – an epidemic of misdiagnoses” by Sally M. Pacholok R.N., B.S.N. & Jeffrey J. Stuart, D.O. under the heading "Types of tests for B12 Deficiency" talking about the Serum Vitamin B12 Test it says:-

However, it appears that these markers demonstrate B12 deficiency primarily in patients whose serum B12 is in the "gray zone" (a serum B12 result between 200 pg/ml and 450 pg/ml). We believe that the "normal" B12 threshold needs to be raised from 200 pg/ml to at least 450 pg/ml because deficiencies begin to appear in the cerebral spinal fluid (CSF) below 550 pg/ml

At this time, we believe normal serum B12 levels should be greater than 550 pg/ml. For brain and nervous system health and prevention of disease in older adults, serum B12 levels should be maintained near or above 1,000 pg/ml.

The book is well worth while the purchase as is Martyn Cooper's "What you need to know about Pernicious Anaemia & Vitamin B12 Deficiency" both available via Amazon - and no, I'm not on commission :)

My interest in this subject is as a result of having had P.A. for 45 years during which (for most of them) I was living in total ignorance of what it was all about and sadly many G.P.s don't treat B12 deficiency seriously. I've struggled for six years to get the frequency of my injections increased in recognition of the symptoms I was experiencing in the run up to the next one.


Just a quick response before going out shopping (in the broiling heat).

People are very good at keeping hold of the B12 in their bodies, so it's recommended to leave at least three months between supplementing and a serum B12 test. Maybe more if the supplementation has been more than normal.

1 like

Thanks fbirder


What's in the b complex? You're not taking too much b6, are you? That causes nerve damage directly. And do you have reference ranges?

Of course I'm not a doctor, but your symptoms sound so, so much like mine before diagnosis. I ended up diagnosed b12d, celiac, Hashimoto's, anemia, with multiple other deficiencies.

I had ibs for years, and the b12d symptoms gradually set in. However, I have never to my knowledge tested lower than 304 pg/ml, which is considered normal range. It is possible to experience nerve damage and deficiency and anemia at this level, but thought to be rare. I suspect it is underestimated.

Even if you don't have the autoimmune PA, the ibs may be interfering with absorption and circulation of b12. You could have something like small intestinal bacterial overgrowth (SIBO) which causes miserable ibs symptoms and affects b12 absorption. My doctor felt my higher folate was a sign of this.

I was lucky I found a doctor who diagnosed me based on symptoms.

I did not tolerate oral b12, I think it exacerbated the SIBO. I got MUCH worse with oral supplements.

IM injections worked better for me, in conjunction with dietary change to improve gut health. Specifically, a celiac gluten free diet, then elimination of most grains, sugar, soy, low fodmaps, etc. I've been mostly on meat, vegetables, and fats. I go by symptoms. Improving my intestinal health has been crucial. I'm reading Dr. Art Ayers' blog on this. I think his info is pretty sound.

I think the b2tekort website is very good about the nuances of b12d. They have quite a bit available in English.

Please feel free to pm me!


Hi Allyson1, I've listed all my supplements in my reply to Gambit at the start of this thread, B6 is 1.4mg in the B-complex supplements. I've also put all the reference ranges in that reply too so I hope that helps.

Wow, it certainly sounds like you were diagnosed with a lot, how are you doing now? Do you feel like they're under better control now you have a diagnosis and know how to treat them? I don't want to find anything but at the same time find it incredibly frustrating that after multiple tests all they come back with is 'normal' and that's just not good enough now. I need an answer so I know how to help relieve my symptoms and manage it better. If not I just feel so low at the thought of having to live with this all for the rest of my life. It was the same with my IBS diagnosis. I've suffered since the age of around 14 with symptoms, but it wasn't until 2009/2010 that I was finally referred to a gastroenterologist and had lots of tests. I was suffering with sickness at least 3-4 times per week, bloating and severe diarrhoea, tiredness etc. tests all came back 'normal' other than the hydrogen breath test which showed I was lactose intolerant (came as a surprise as I've always loved drinking milk!). I've replaced normal milk, cheese, cream and other dairy products with lactofree products for the past six years and it has definitely improved my symptoms. I still suffer daily with a constant bloating feeling and diarrhoea but I learn to live with it (eating out is a nightmare which I mostly avoid or we end up getting the bill quick - the joys of living with IBS where your digestive system rules your life!).

It's interesting that you don't believe you've tested lower than 304 and yet they have given you a diagnosis. Even when I questioned my previous readings of 237 and 244 with my GP (given he said anything under 197 was a deficiency) and how close they were to the lower of the range he said they were still perfectly normal.

Thanks so much Allyson1, I think I'll try and get around to messaging you to pick your brains a bit further based on the fact you say my symptoms sound similar to how you started out. Living with IBS gets me down a lot of the time but I try very hard to keep it under control. I've kept countless food diaries and can now pinpoint a lot of things I just avoid full stop, i.e. certain spices etc. but with IBS always comes the annoyance that you can eat something one day and be perfectly fine, eat it the next week and suffer with a terrible flare-up which worsens my IBS then for anything between a couple of days to 2 weeks.

Thank you again for all your advice :-)


I find it strange that you have had the parietal cell antibodies test , but not the intrinsic factor antibodies test ,which is the usual one although this is not conclusive. If you are taking B12 supplements by mouth without any improvement , it sounds like an absorbtion problem ( I. e. PA) I have PA but also tested negative to the parietal cell test . If you have PA , the best treatment is B12 injections for life . I had been taking B12 in every shape and form ,(except injections ) and as a result had a sky high reading when I was tested . This high level meant nothing as I had absorbtion problems . After 5 loading injections I felt so much better , but was unable to function on one injection every 3 months . GP. refused to give me more often inspite of numb feet so now I self inject to keep myself well . Gastroenterologist told me that PA patients have low or no stomach acid (hypochlorhydria and Achlorhydria ) which results in those IBS symptoms because of the loss of stomach flora . Bad bacteria is not killed off by the stomach acid and takes over , simply put.You then get stomach pain, bloating and burping caused by the gases created . Try to help this situation with probiotics Symprove helped me . I took it for about 4 months and it was marvellous I then cut down and now just take home made organic sauerkraut ( you can buy it in health food stores usually or online) The NHS has no treatment , so you are on your own . Some people also try drinks of diluted organic cider vinegar with honey or lime juice . There are hydrochloric acid betaine with pepsin capsules which some people take with meals , but I didn't dare . ( Google ) Dint know if my experience has helped at all . Dealing with PA is so tricky as the medical profession is ignorant about it , and you are often on your own with it . When you are feeling so unwell and have to cope with this ignorance , life is difficult . I hope that you find a solution We are here to support you . Best wishes


Hi Wedgewood, thank you for you advice and support, it really is appreciated as I feel so disheartened by it all and it's really getting me down. With the parietal cell antibodies test, there was a note written on the test results reading "Gastric parietal antibodies are a more sensitive marker for pernicious anaemia than intrinsic factor antibodies, are the latter still required?" so I take it from that, they didn't do the intrinsic factor antibodies. Thanks for the advice with the probiotics, it's something I've wanted to look into but not really known where to start and I suppose I just have a fear of making my IBS symptoms worse. If you self inject for B12, where do you source it from if the NHS/GP won't provide more than 3 months? I feel like I'm going to have a real fight on my hands to even be allowed an injection, let alone a course of them so I want to go in there with a strong case of why I should be eligible based on all of my symptoms (it's the neurological-related symptoms like the unsteadiness, pins and needles, confusion and lack of concentration that are really concerning me).

Thank you again for your helpful advice!


Forgot to say that member @fbirder has a link to lots of scientific papers which you should print off and take to your doctor . I bet he will be in touch with you .


I felt exactly like you do before the injections . We can only get B12 ampoules on prescription I. UK for some unknown reason . I get mine from Germany . I go there twice a year to see my daughter, and can buy them in an Apotheke over the counter - no problems ! But you can buy them from Amazon de( German Amazon ) and from many German online chemists . I have just bought 100 for about £56,so you see they are not very expensive . Syringes and needles are easily bought in UK .

Regarding the parietal cell tests mine came back negative but Intrinsic Factor was positive . Trouble with the IF Is that it often shows negative falsely . Martyn Hooper our founder had that problem . But it is known in the medical profession . Your symptoms should be treated , not blood readings . B12 is cheap and harmless , and you cannot overdose on it . By the way if you do buy any ampoules it should be the HYDROXOCOBALAMIN form .

It is usually a terrible fight to get B12 treatment . Why? I'd better not say what I believe here . So don't expect it to be easy but. I do suggest you try the Symprove though for the IBS symptoms . Google it and you will find info. It was brilliant for me . It is expensive I warn you .

You have friends and allies here on this forum . Do not hesitate to get in touch . All good wishes .


Chipping in to say that I have had IBS on and off for almost 40 years, when diagnosed and treated for PA 15 years ago it cleared up for a long time. It has been back with a vengeance for the last year and I took note of Wedgewood's and others' rec for Symprove and will finish my first 4 weeks supply in a few days, the second batch has arrived and ready to go (offer direct from Symprove of buy first 8 weeks and get the last 4 weeks of the 12 week plan for free). Very helpful company to speak to on phone and I have been seeing improvement for a couple of weeks now. It (like the treatment for PA/\b12 def) is not a linear improvement and I have had some horrid episodes of diarrhea since, but assumed that it was the bad bugs being killed off. (No affiliation to the company)

My situation is a bit complicated ATM, PA, hyper low Ferritin found 18 months ago, tests and more tests, now have Ferritin raised from 7 to 88, more bloods next week, and assumed that all my symptoms, (a lot shared with you) were down to PA, very recently diagnosed with a rare immuno-deficiency condition which I infuse the treatment for weekly. I decided to SI with hydroxycobalamin (sub cut) with recommend co-factors, thinking it can do me no harm and might just give my body a boost in order to make best use of the antibody replacement. The real purpose of the last bit of waffle is to say that I am very happy with sourcing my supplies from Germany by post and all the needles etc from the U.K.


OK a few points to cover.

First off - my summary document is here - frankhollis.com/temp/Summar... - lots of useful stuff extracted from expert sources - and where in those sources to find the important stuff.

For a while the anti-GPC test hasn't been recommended by the experts - onlinelibrary.wiley.com/doi... - the anti-IF being preferred, despite its problems.

Regarding the variation in your B12 levels. Not only can it vary naturally, if you supplement then that can help make it vary even more (depending on the time between supplementation and testing. However, your results (247, 234 304) could well be due to the variation in the assay. It can be up to +/- 20%. So if your true level was 270 then the assay could give results between 226 and 324.


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