Not new here but just a little background - I was diagnosed with B12 deficiency back in 2014, I managed to produce enough evidence to satisfy my GP that I could not manage on 2 - 3 monthly injections and so I am able (currently) to access enough B12 for my needs, but this could soon change due to GP being on long term sick.
Early 2018 I was diagnosed with Type 1 Gastric NETs (Neuroendocrine Tumours), during that investigation it was shown that I do not have any parietal cells, intrinsic factor or stomach acid - I have autoimmune atrophic gastritis and high levels of gastrin, as would be expected. My NETs do not give me cause for concern and I have yearly endoscopic surveillance.
There is always a rake of blood tests when I go for my surveillance and my B12 always comes back high 2000 + ng/L along with high folate 24 + ug/L (my ferritin has been slightly below normal values the last 2 years, as has my RCC - red cell count), my NET specialist advises 2 months of Iron supplementation each year.
After my surveillance this year my NET specialist said he wanted me to cut down on the amount of injections (I inject on alternate days and have done since my diagnosis), as my serum B12 level results were too high, and that there is a school of thought that says this is dangerous (I know it is not of course). There was a paper published in 2020 about high serum B12 and all cause mortality that caused a bit of a stir, but the authors neglected to point out that they did not include anyone who was already supplementing (they wrote an amendment later on to correct this omission, stating that supplementing with B12, for proven medical reasons, would of course produce raised levels so these people had to be excluded from the study). I did try to do as he requested and very soon my symptoms began to return and I felt really ill again, so I resumed my normal routine and am ok again now (he has since forgotten what he asked, it seems, and, at my last virtual appointment, said to me 'you're still taking your B12 aren't you, because you need it'. )
After that long ramble of a post, my question is -
Why are my serum B12 levels so consistently high over these past 3 years? I thought they peaked and then began to stabilise a little when I.M supplementation was sufficient to treat the symptoms, is this correct or am I way off? Is this normal when you are supplementing?
I'm pretty sure the locum GPs we have at the moment will question these levels and try to stop my injections (they already have with one woman I know) so I could do with knowing what I'm talking about in order to stand my ground. Thank you.
Apologies for the long post.
Written by
Wierdorwhat
To view profiles and participate in discussions please or .
I'm no expert but my understanding is that the serum B12 test only measures what is "swirling around" in you bloodstream not what is actually getting into the cells where it is needed and that any excess to requirement is excreted via your urine.
High levels of B12 in anyone NOT INJECTING OR SUPPLEMENTING BY ANY OTHER MEANS may be an indicator of other possibly dangerous medical conditions.
I think the report you are referring to was later "debunked", amended and qualified to exclude P,A, sufferers and anyone needing to supplement with B12.
I hope that you will be able to open the link below
Yes, I was able to open the link and it contained pretty much the same as I'd read on other sources - I can provide those links if you would be interested.
That's what I thought, good to hear it from someone else though, that what's in the blood isn't all useable.
Hopefully I'll be able to use the info provided in all the answers from you all.
Wow! Another person with gastric NETs! I am not alone! And I need to inject frequently (twice a week)l although my GP wouldn’t prescribe more often than once a fortnight, so I buy my own as well.
Our B12 levels are that high because we keep pumping it into our bodies - because we need to. Nobody knows why some need it frequently while others can get by with a top-up every few months.
I recently changed GP. The new one questioned why I was getting B12 prescribe twice a month. I explained that I showed the old GP my symptoms diary and he agreed to more frequent injections.
“So he based that decision solely on your symptom diary,” she asked. “Not your blood levels?”
“Yes,” I replied. “He thought it better to treat symptoms rather than numbers.”
Stunned silence and movement on to the next subject. No change to my prescription.
yes, I had noted that you seemed to be the only other person here who has gastric NETs, we're an exclusive lot aren't we
So it's as simple as that then, the frequency of the injections, that registers us as having high levels of serum B12?
I think I've read somewhere that there is active and inactive B12, I'm a bit vague about what I actually read as I have another illness that causes the dreaded brain fog (hyperparathyroidism) so I sometimes don't retain what Ive read - would that be anything to do with the high levels or not?
It's so difficult to convince the GP's isn't it? I'm not looking forward to this when and if I'm challenged by the locums.
Glad to hear that your prescription hasn't been changed.
Many people seem to think this is a matter of great import. It really isn't, except for a tiny number of rare cases.
The B12 in the blood is bound to one of two proteins - haptocorrin (HC) or transcobalamin (TC). TC-B12 is the only stuff that can enter cells, so it's called 'Active' B12 (or, sometimes, holotranscobalamin).
Nobody is quite sure of the purpose of HC-B12. I believe it's to mop any any B12 analogues that happen to get into the blood. Lots of foodstuffs contain chemicals, called corrinoids, that look a bit like B12 but are biologically inactive. It's why lots of sources say that some plant foods, like nori, contain B12. They were analysed using ancient techniques that couldn't tell corrinoids from real B12.
The ratio of HC-B12 to TC-B12 is around 4:1. The normal serum test measure both types. The 'Active' test only measures TC-B12. So you would expect the serum test to give values about 5 times higher than the 'active' test.
Some people think that this is a reason to distrust the serum test, because most of what it's counting is inactive. That's totally wrong. I always liken it to counting sheep as they run past you. You can count heads or you can count feet (and divide by four). Both methods are equally valid.
So why do people place so much emphasis on the 'Active' test? Well, the serum test is neither precise nor accurate. You can measure the same sample twice and get results that vary by more than 10%. The 'Active' test is supposed to be much better (the 'Active' test also has better PR people). But it still has the same problem as the serum test - the big overlap between normal people with low B12 and deficient people with normal B12.
Thanks for all that information, very useful. If the "active" B12 is the important measurement and the NHS don't measure that in blood tests, do you you personally measure that and through which outside testing facility. Also does the "active" part have an acceptable range?
My NET expert at King's College Hospital wrote a great paper about gastric NETs. In it he says the incidence of gastric NETs is 0.2 per 100,000 or 2 in a million.
The real question is why is your doctor trying to base your treatment on blood levels when that is discouraged by the NICE and BCSH guidelines. The test is just too difficult to interpret post injections. Your levels will be in an eternal state of flux if you are on injections - off the scale post injection and then falling over time but the rate at which they will fall varies enormously and can be years, This doesn't correlate in anyway to when symptoms recur. The exact reasons for this isn't understood,
Good question, and the answer is I don't know, but it seems to indicate a lack of understanding on his part, which is somewhat worrying when he is a NET specialist and a Prof of gastroenterology.
I'll dig out the guidelines if I can and highlight the text for him.
Content on HealthUnlocked does not replace the relationship between you and doctors or other healthcare professionals nor the advice you receive from them.
Never delay seeking advice or dialling emergency services because of something that you have read on HealthUnlocked.
B12 blood tests after supplementing?
B12 deficiency with High Serum B12?
Recent PA diagnosis, serum levels high from oral cyanocobalamin, symptoms persist
B12 levels
Can someone Interpret this article for me?
