Serum b12 levels.

[KathyN]

Hi, I just want to query advice given at times here on serum b12 levels. As somebody who has had b12 problems and has hypothyroidism I find the common suggestion here that serum b12 should be at least 500 quite confusing. In fact I have read a comment on the PA forum very recently by one of the administrators saying that this was often stated on the thyroid forum and was an 'urban myth'. The serum b12 test is now regarded as being pretty inaccurate and the active b12 test is being used more and more. I have recently been a patient at Guys in London and was told by them that they do not use the serum b12 test at all as it is so inaccurate. The active b12 is available more and more now and bloods can be sent off to St Thomas' by your GP or it is available for private testing by blue horizon and probably others. Just to give myself as an example my active b12 is now consistently really high, off the scale, but my serum b12 always sits around the 200 mark. I must just say thank you so much to all you guys on the forum, I can't tell you how much you have helped, I'm not an avid poster on this forum but am an avid reader!

[bantam12]

So what level does the PA forum advise using the active test ?

[KathyN in reply to bantam12]

Not sure that they do, you need to check with them, the ranges are completely different. St thomas' automatically refer low active results for mma and homocysteine.

[Marz]

Thank you for your post ....

Many bloodtests are just guidelines - and good docs look at them along with the symptoms. The Active B12 Test is comparatively new - so the serum test was all there was for many and still is. Not everyone can afford the Active Test. Also trying to get a NHS GP to test MMA & Homocysteine is also a dream it seems.

Just yesterday there was a link posted on the PAS Forum explaining why Hypos need more B12 and other vitals.

As an example I had my Terminal Ileum removed over 43 years ago and was not told I would need B12 injections. My levels were always above 300 so I would have been told by PAS Admin that I was fine. I live with the consequences of having lived with Low for me B12. Weekly injections for the last 3 years have helped to improve things a great deal.

The urban myth - as quoted - came from Sally Pacholok's book - Could it be B12 ? It is mentioned there are changes in the cerebral fluid when levels are below 500. The book is suggested reading on the main website of the PAS so cannot be all bad.

Having been on this forum for almost 6 years I have observed the huge issues surrounding low B12 when accompanied by low Folate - Ferritin - VitD and thyroid issues. With almost 62,000 members here - lots of experiences have been shared.

We are all individuals and should be allowed to think as such. Of course it is confusing when told one thing and then another - so we have to decide which horse to back ! Thyroid and B12 seem to share the same desert when it comes to correct testing and treatment 😊

Am pleased for you that you have been diagnosed and getting the right treatment - here's to wellness 😊

[KathyN in reply to Marz]

Yes I completely agree it is all very confusing. In the future the active b12 test will replace the serum and we will all be better off. Of course symptoms are the most important thing to go by and I don't suppose many tests are infallible. In my case all my symptoms were blamed on low b12 and it wasn't until active b12 was done that my symptoms turned out to be thyroid related and I was treated. Sally Pacholok's book is indeed brilliant but as is stated on the PA forum the serum b12 test isn't a gold standard test - it will miss 25% of people who are b12 deficient but also pick up 5% who aren't as a single measure. I asked my GP for the active test and although she had never heard of it she researched it, took my blood and posted it of to St Thomas', I am really lucky to have a doctor who seems to care! It's so sad that we all have to fight for the for the right treatment but it is great that at least there is lots of information out there in these forums.

[Marz in reply to KathyN]

healthunlocked.com/api/redi...

Sadly there is not enough scientific research into B12 and its effects .....

[Polaris in reply to KathyN]

I have to say that I'm at a loss to understand why the question of B12 serum test under 500 keeps arising, as the latest BMJ research document (peer reviewed and with many references), clearly states there is no reliable test and, as Marz has already explained, symptoms are paramount, especially if they are neurological because there is a short window of opportunity to treat before damage is permanent :

" BMJ Research Document - Summary points below:

Vitamin B12 deficiency is a common but serious condition

Clinical presentation may not be obvious thus leading to complex issues around diagnosis and treatment

There is no ideal test to define deficiency and therefore the clinical condition of patients is of the utmost importance

There is evidence that new techniques such as the measurement of holotranscobalamin and methylmalonic acid levels seem useful in more accurately defining deficiency"

If the clinical features suggest deficiency then it is important to treat patients to avoid neurological impairment even if there may be discordance between the results and clinical features "

"Severe deficiency shows evidence of bone marrow suppression, clear evidence of neurological features and risk of cardiomyopathy.

***It is important to recognise that clinical features of deficiency can manifest without anaemia and also without low serum vitamin B12 levels. In these cases, treatment should still be given without delay."

pernicious-anaemia-society....

[Clutter]

KathyN,

I believe the advice about B12 serum needing to be 500 comes from Sally Pachalok's book and the oft stated belief that the Japanese consider anything below 500 deficient.

I tend to advise members with serum B12 >350 that they are unlikely to be deficient but if they have symptoms of B12 deficiency to contact PAS for advice.

[Gambit62]

active B12 has one major advantage of active B12 in that it will measure just the B12 in your blood that is bound to transcobalamin11 and hence available to pass to cells.

For most people the ratio of transcobalamin11 to B12 bound to other proteins will be 20% but in a few people it can be out of kilter and may be much lower than this - or even much higher.

both serum B12 and active B12 tests look at amounts in blood. But there can still be variation in how much B12 is actually getting through to cells and whether cells are able to use that B12 that won't be picked up by either test ... and its whether your cells have the B12 that they need that really counts.

People can experience neurological problems with levels below 500pmol/l, and should be treated if they do but this is a diagnosis that is based on clinical evaluation (ie looking at symptoms). The guidelines that apply in the UK are to treat on the basis of symptoms if there is a discordance between symptoms and test results but evaluating symptoms can be very difficult as these overlap with a number of other conditions that are often clustered together.

The basic message is that you cannot use serum B12 results as a guide to whether you should supplement or not. You need to look at whether you have symptoms. However, if there is a chance that symptoms are due to another condition then it would be better to rule that out before jumping to high dose supplements. There are also a couple of test that may help to clarify what is going on at the cell level (MMA and homocysteine) but again these tests need to be taken in context that rules out other things that can cause them to be raised.

Supplementation with high dose is unnecessary unless you have an absorption problem and can be problematic as some people respond to high serum B12 levels by shutting down the mechanisms that allow B12 to be transferred from blood to cell, leading to a functional B12 deficiency. Whilst this can be treated effectively by keeping serum B12 levels continually high this seems to be introducing an unnecessary and potentially expensive need to continually supplement - and can also cause huge problems in terms of getting conditions diagnosed.

One common symptom of B12 deficiency is macrocytosis (enlarged and rounder red blood cells). This is also a symptom of folate deficiency. However, it is a symptom and not a defining characteristic and also isn't present in 25% of people who aren't B12 deficient.

Diagnosing B12 deficiency is difficult but is made more difficult but lack of understanding of the real significance and limitations of the tests involved. Unfortunately this isn't unique to B12 deficiency. It can also apply to iron deficiency and, particularly relevant to this forum, Thyroid problems.

[Marz in reply to Gambit62]

Thyroid sufferers have absorption issues as reflected by other test results and shown daily in the results posted.

[Gambit62 in reply to Marz]

I am aware that thyroid sufferers can have absorption issues but again, it doesn't affect everyone and that doesn't alter the fact that serum B12 or even active B12 on their own should not be used as single determinants for supplementation/treatment.

And I also very much appreciate that evaluating symptoms is difficult with such an overlap between conditions.