Hi
I want to get my vitamin B12 levels tested. I’ve read somewhere that you should only have a blood test something like 4 months after stopping any B12 supplements …..
Is this correct ? I have been taking 1 x Jarrow B12 2500 mcg sub lingual tablet plus a spray each day for past 5 years. I’m a bit worried about stopping the supplements for such a long period in order to get a true reading on the blood test …..
There is absolutely no point in testing, since you've been taking a daily dose of b12 for 5 years.
You would need 6 months off the supplements to gain am accurate reading.
Its a sad truth that most of us have to self medicate based on symptoms. But if you want a doctor to check blood levels as accurate, and based on your current diet, you'll have to stop taking them.
Yes, I realise I need to stop supplementing for quite some time before testing but the concern I have is that the tablets / spray are no longer doing a good job. My father had PA and was getting B12 injections every three months. Unless I can show low B12 levels in my blood this is an option that won’t be open to me…..
What is your GP like? Do you think they would be willing and able to diagnose PA for you?
Can I ask why you take daily b12?
They might but only if it’s below range and it won’t be unless I stop supplementing. I take daily B12 because I need to - I found this level keeps symptoms at bay but recently they’ve started to return…. Although I take large amounts of B12 I’ve no idea how much of it is absorbed/ active in my bloodstream!
You could join the Pernicious Anemia Society and contact the helpline. Or email them. It may be better to try a private test but they'd be the right people to consult I should think
If you have PA then I doubt the supplements you have been taking would have much effect on your levels. I would go ahead and ask for a routine blood test including B12 levels in view of your family history. Then you might have some idea of how things are
This is my feeling exactly….. the supplementing orally worked for a while but not any more. It’s been suggested I do a blood test for intrinsic factor but as that’s not always accurate I see no choice but to stop supplementing in order to get a true reading of my natural B12 levels. I just wondered how long that process will take, hence my original question…..
If you have PN the oral supplements will not effect your blood test because you won’t have been able to absorb them.
Not sure what PN is but think you’re wrong about not affecting the blood test …..
I need to stop supplementing in order to get an accurate reading of my natural B12 levels before going any further….
Are you really willing to suffer the possible impact of a plummeting B12 level? Bear in mind that some effects of low B12 cause permanent damage that can never repair.
It would appear more sensible, at least in the first instance, to request an Intrinsic Factor antibody test. If that is positive, you have proved PA. (Even though around 50% of tests are reported to be false negatives, it surely makes sense to see what that shows?)
Sorry I meant Pernitious anaemia. I still think if you are only taking oral supplements you should go ahead and have a blood test to see if you have a low B12. Then you would have a reason to need injections. That is starting with loading doses. Good luck what ever you decide.
I take your point but it seems like a case of I’m damned if I do and damned if I don’t ! ☹️ That’s a good point about getting tested for IF though, but whether I can convince a GP to do that is another matter ….
Unfortunately the catch 22 of treatment/self-treatment is what most of us have to face. GPs aren't helpful if you test within a normal range
I think still possible to test holo transcobalamin but its not accurate
Have your b12 levels been low in the past and have you had an intrinsic factor antibody (IFAB) test to diagnose PA?
I heard you need to be off of all B12 for 4 months for the B12 blood test. 2 weeks for intrinsic factor. Expect a fight over getting injections. My B12 was at 250 when they started me on 5000 sublinguals. It brought my bloodwork up to 800 after 2 years of sublinguals. I got worse, but doctors refused to even consider injections because my bloodwork showed 800. I saw so many different doctors, but one look at my 800 and they said it wasn't B12. I got really bad with the numbness and tingling. Then I was having trouble breathing. My eyes got blurry, I fainted 3 times. At the cardiologist they put me in a wheelchair, because I couldn't walk. Finally, a nurse practioner listened to my symptoms. She started me on weekly injections. I am slowly getting better. My B12 is over 2000 the day I get an injection and 6 days later it's around 1100.
Thanks, looks like I’ll have to stop supplementing for a few months then …. it’s interesting that you started on sub lingual tablets and then found these were no longer doing a good enough job - that is where I feel I’m at now ☹️ My father had PA and my B12 level before supplementing was 254. I had several neurological symptoms that went away within a week of starting on Jarrow 5000 mcg B12 sub lingual tablets six years ago but more recently some have returned….
Even after 4 months your b12 levels could be high. Circulating in your blood but not reaching the cells.i personally give your symptoms and say the oral dose isn't doing the job anymore . That and your family history surely would get you an IFA test and b12 injection trial. If you stop log your symptoms
I agree with previous posters about the danger of stopping B12. I take oral B12 and, before I knew any better, stopped taking it because my GP said my B12 was 1800 and could be dangerous. Within 3 weeks I was getting symptom back. When I started fainting I knew I had to start taking it again. And I also knew my GP hadn't a clue about B12D. If you're the same as me I don't think you'll be able to give up your oral B12 without endangering your health. Maybe if you need to up the amount of b12 you take. Less than 1% of oral b12 is absorbed. It is via osmosis which is very inefficient. I take three times the amount you do. I dissolve liquid B12 in water and drink it throughout the day.
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Would blood tests 3months after last b12 injection be accurate?
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Blood test & B12 supplementation
