A post earlier today said that anything less that 550 pmol/L was considered deficient in Canada. People from TUK often say that 500 pmol/L was needed.
So I decided to look at the data. I found this study wherein 961 people had their serum B12 tested. cambridge.org/core/services...
The mean serum B12 was 312.88 pmol/L and the Standard Deviation was 135.98 pmol/L
That means that 68% of the healthy people will have a serum B12 of between 176.90 (mean - SD) and 448.86 (mean + SD) pmol/L. 16% will be below that lower limit and 16% will be above. Using my (not very good) knowledge of statistics I make that about 10% of the population with a serum level higher than 550 pmol/L
So, in this group of healthy people (people with a diagnosed deficiency and other possibly related problems were excluded) 90% would have been diagnosed as deficient with a lower limit of 550 ph/L!
Now, this assumes a normal distribution (which I doubt it is) and it doesn't say what type of assay was used, but it demonstrates that 550 pmol/L is way above what anybody would consider 'normal'.
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fbirder
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Think there is a huge difference between statistical averages and where any individual falls in a range.
It isn't that the Japanese just treat anyone who scores under 500 - they will be using that as a cut off point for considering B12 deficiency and looking at symptoms etc.
is there any evidence (apart from that one Wikipedia article mentioned by Hidden ) that says that they treat anybody below 500? Because that paper Eaoz cites suggests that over 99% of the Japanese students in that study would require treatment!
550 pmol/L is about 4 SDs above the mean which means, if it's a normal distribution, the chances of having a level above 550 is about 1 in 8000.
i do not believe there is any peer-reviewed, scientific justification for saying that serum levels below 550 pmol/L need treatment. And I say that available statistics show that the vast majority of healthy individuals would fall under that value.
Extract from Pernicious Anaemia:The Forgotten Disease by Martyn Hooper
"...In their book Could it be B12? An Epidemic of Misdiagnosis Pacholok and Stuart propose that '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 1000pg/ml'. The main reason they advocate this is because in the grey zone of somewhere between 180 and 350 pg/ml many patients present with all of the symptoms of pernicious anaemia but the physician is reluctant to begin treatment because the 'borderline' reading could be corrected by changes in diet."
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."
My phone is not cooperating with me today, but I believe there is a unit conversion issue here. In the US (and probably Canada too) the serum B12 is measured in pg/mL, not pmol/L. That means the low end of the reference range is higher in the US (around 200) than in the UK (closer to 180).
There is still a big difference between 200 and 500. My point is only that unit of measure does make a difference in coming up with statistics.
Hashi's sufferers have usually had enough problems with diagnosis and treatment on flawed TSH tests, without having to struggle to be heard on this forum, especially when the autoimmune thyroid connection with B12def. is mentioned in BCSH guidelines as an added risk.
Maybe left brain could take a break from looking at statistics FB, to read Sally Pacholok's excellent book, 'Could it be 12 ? - an Epidemic of Misdiagnoses', (although enough statistics in there to prove her case), in which she and her husband, Dr Stuart, recommend a serum B12 level above 550, for seniors - 1000.
It is so clear after reading this book and the way B12 def. affects the body and mind of all ages in such diverse ways, that the cost of treating patients with B12 is minimal compared with the devastating risk of misdiagnosing and not treating! Sally and her husband worked on the frontline emergency department of a large city hospital, so observed firsthand the enormous human cost.
In any case, isn't the test result slightly irrelevant when latest BMJ research concluded there is no reliable test and, therefore, important to treat without delay on history and symptoms - even more so when neurological effects are so subtle and with referrals to specialists now taking such a long time.
One of my relative's GP's admitted that medicine is now too test based but she still had to battle for her surgery to treat her thyroid and severe B12 deficiency adequately.....
PS. As seen so often on this forum, medicine is indeed so test based now that, even if GPs do read the research and treat, they do not bother to understand the complexity of the deficiency and assume that, because levels go high, treatment is no longer needed.
This study seems to refer to normally behaving B12 population. The people with B12 deficiencies on this site for instance do not belong to that distribution and obviously have a completely different distribution. IN fact there seems to be different distributions applying to the people on this site.
This popped into my Inbox today - not wishing to go against the grain - am just being informative for others - that may be at the beginning of their journey of understanding.
Chris is American which you will no doubt glean from the narrative .... There are some helpful hints within ....
That is excellent article Marz - shows how complex B12 deficiency is and how important to have a clinician who sees many cases and is experienced in seeing past a test result only:
"And so, if you get the B12 tests back and the level is 300, it’s going to be marked as normal, but at that level there’s a really good chance that you are in the earlier stages of B12 deficiency, and then if you were to measure homocysteine or MMA, that those would be out of range as well. With homocysteine, the range typically goes up to 13, 14, or even 15 in some labs, but I’ve seen lots of research suggesting that with B12 or folate deficiency, that can show up on homocysteine levels, start getting higher than eight. Homocysteine level above eight doesn’t necessarily reflect B12 deficiency, but it would be cause in my mind for doing further testing. Keep in mind that homocysteine is an inverse marker, which means when it’s high, that suggests B12 is low, and both serum and urine methylmalonic acid are also inverse markers, so when they’re high, that suggests that B12 is low.
Be aware that high serum B12 does not necessarily rule out functional B12 deficiency. This is what I was referring to when I said there’s some nuance on how to interpret these markers. In fact, I have come to view a high serum B12 when the patient is not supplementing or not eating really extreme amounts of B12 foods like liver as a potential red flag for active B12 deficiency."
How does one measure in comparison to the one used in Canada the range of 500...If someone has a UK test twice done & comes back at 304 & 340 how does it come to in comparison with other testing abroad can it be calculated?
With serum B12 tests one has to bear in mind that there are always variations between tests in different labs (which is why we see different 'normal' ranges) but also variations between different tests in. The same lab.
For serum B12 I've seen estimates of 10 - 20% variability within the same lab. So your results of 304 and 340 are, essentially, identical. All we can say is that they are quite a bit above the range that would normally be considered as being deficient.
But the whole point is that serum B12 levels are, essentially, meaningless. Just because you have a serum B12 of 340 doesn't mean that you're not deficient. Equally, it doesn't mean, as some people imply, that you are deficient.
What matters is are there symptoms and, most importantly, are those symptoms relieved by additional B12?
I've always said that the only real test for a B12 deficiency is: does the patient have symptoms that are relieved by giving them B12?
"I've always said that the only real test for a B12 deficiency is: does the patient have symptoms that are relieved by giving them B12?"
Totally agree with your last sentence fbirder .
I would also add that I think any trial of b12 treatment should be of a reasonable length.
I was unable for many years to get NHS B12 treatment despite being highly symptomatic due to majority of tests being "normal" range and IFA test negative.
When as a last resort I started to self treat, many symptoms (including neurological symptoms) disappeared but it took weeks to see a difference.
I was thinking as well of just increasing until I am in the 800 range & keep it there what at your thoughts but at the same time watching iron folate all levels as well as I go up I am tired of testing bak and forth all the time plus go on a very strict (HFI) diet eliminating sucrose fructose fructans lactose gluten altogether...I cannot even tolerate Gluten-free garbage useless foods at all I will get my fiber from other sources & eat Fats as well
Thanks for doing the research and for the clarification. I wonder, what does this mean in the context of dialogue with the medical profession and trying to get diagnosis and treatment? The Pacholok proposal of higher levels being 'normal' was useful for that - but you are saying it is wrong and shouldn't be cited? The majority of doctors, as evidenced by posts here, will take the normal range as concrete evidence for diagnosis and treatment. It's no good saying they should treat on the basis of symptoms - first they have to accept and believe that you have those symptoms (which are largely invisible) and that they have a physiological basis (rather than being a mental health issue requiring anti depressants) and that the symptoms are significantly disabling to require treatment. If the B12 levels are 'normal' they generally won't go on to test further.
Was the Patchlok proposal useful? How many doctors are going to be persuaded that an unknown author of an unknown book is a more reliable source than the experts that set the recommended ranges.
Yes, you know, and I know, that these ranges don't seem to have basis in evidence. But the doctor isn't going to know that. He will assume that the official 'normal' ranges are based on something sensible.
And, if a doctor was intrigued by the idea of the official range being erroneous then she's not going to accept the stuff in that unknown book, she will do what I did and search the published scientific literature. And it wouldn't take her long to find the same as I did - that treating everybody with a serum level below 500 pmol/L is nonsensical.
If they do read Patchlok's book they will be confused. After reading 'we believe normal serum levels should be greater than 550 pg/ml... In older adults serum B12 levels should be maintained near or above 1,000 pg/ml' the doctor will turn the page to find 'we advocate treating all patients who are symptomatic and have serum B12 levels under 450 pg/ml'.
Confused? I was. They seem to be advocating treating everybody with levels below 550, except for people with symptoms?
At this point the doc will look at the cited papers, and find that they're all about 30 years old! Is there nothing more recent? Let's look - and they find the recent papers saying that most people have levels well below 550.
So, how do we persuade our doctors? We give them material they will recognise - the BMJ review article, the recent article in Blood, and the BCSH and NICE recommendations. These will not be pooh-poohed. They all mention the unreliability of serum B12 assays and how they often fail to match symptoms.
And we support the PAS, who are working to educate the medical profession by explaining things.
Edit: I've just read that the PAS are working with NICE to get diagnosis guidelines improved. That's the sort of thing we need.
That's very useful advice, thank you. Hope it was ok to bring it up - you've definitely given me the answers I was looking for. Good news about PAS and NICE.
Personally I have had 'some' mileage from the Patcholok proposal in that it gave me the confidence to refute the 'normal' diagnosis, and become aware for the first time of the flawed testing system. Of course if you are coming to all this for the first time and are not of a scientific/medical background, the book is quite eye opening. I had thought it was a recommended read - I must have been mistaken.
Anyhow, to have reference material which WILL be taken seriously and is up to date is a great improvement.
I honestly, cannot see how nitpicking Sally Pacholok's advice re test results is helpful to people searching for answers on this forum.
It is difficult to imagine time pressed GPs ploughing through reams of research when, in reality, very few will even read or attempt to properly understand the well summarised and researched BMJ document, let alone official guidelines, which, according to the many comments in 'Pulse', many deride anyway!
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