All my bloods were normal (including negative anti bodies for intrinsic factor) other than my Vit B12 at 130. I then took 1000mg of Vit B12 sublingually for 18 days and had a blood test taken 6 weeks after the first one and my Vit B12 levels had gone up to 200. From this, should I assume that I CAN absorb B12?
I am also quite confused by how one can actually get diagnosed with PA as from all the info that I have read on the PA Soc site suggests that there is no definitive test therefore no proper diagnosis can be made only an assumption. Is this correct?
I would really appreciate someone's wise words.
Many thanks.
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Hambledonia
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PA diagnosis - IFA is the test used to diagnose PA as a specific cause of B12 deficiency. However, its not very sensitive so gives false negatives 40-60% of the time. It is very specific though so rarely gives false positives.
This means that a positive on this test is a good indicator that you have PA. A negative is a long way from proving that you don't have PA.
You could take the test a number of times until you get a positive but ....
Although most B12 is absorbed in the ileum a small amount (averages 1% is absorbed outside the ileum, so taking large doses orally can result in enough getting through even if you have an absorption problem - though it isn't a particularly efficient way of raising levels.
There are limits to the accuracy of the B12 serum test which means that if you repeated the test on the same sample a number of times you would get results that varied by about 20% - the rise you report is outside this which implies that you may be absorbing some B12 from the tablets but it is only just raising your B12 levels.
I don't think that two readings of 130 and 200 can tell you anything about absorption. If your real levels were 160 then normal errors in the test could give those numbers. But I would have expected a large increase in blood levels if you didn't have any problems.
There is no definitive test for PA. In my opinion there are two criteria that should be sufficient for a diagnosis.
1. The patient has a B12 deficiency - determined by whether their symptoms diminish when treated with B12 injections.
2. There is no obvious cause for that deficiency (diet, PPI use, H. pylori infection, metformin, NO abuse).
If both those boxes are ticked then PA should be the diagnosis.
Thank you both for your replies. So informative and helpful. I had been wondering whether I should get excited about the fact that my B12 had risen after 16 days and that I might not have PA after all. It would appear not!
Fortunately my doctor has recommended injections anyway although I am anxious that I might have a bad reaction as I think my face reacted (swelling, heat and hives) from taking the methylcobalamin sublingually. Fortunately the injection is hydroxy version.
I did just wonder if it makes a difference where the nurse injects?
Immediate adverse reactions to hydroxocobalamin are very rare. There may be some intermediate term effects after the first few jabs (you may feel more fatigued, you may get acne) but they go after a while.
The nurse will want to put it into your arm - that's what they are used to and most comfortable with. The site doesn't make any real difference.
If you eat plenty of B12 rich food eg meat, fish, shellfish, dairy, eggs, foods fortified with B12 then diet a a cause becomes less likely and it becomes more likely that there is an absorption problem in the gut eg PA, Coeliac disease, H Pylori infection plus other possibilities.
Coeliac disease
NICE guidelines Coeliac disease recommend that anyone with unexplained B12, folate or iron deficiency should be tested. Has your GP tested for Coeliac disease?
Two tests are recommended in NICE guidelines.
1) tTG IgA
2) Total IgA
UK GPs sometimes only do tTG IgA even though guidelines say to do both.
tTG IgA checks for a particular antibody to gluten.
Total IgA looks for people with IgA deficiency.
People with IgA deficiency need other tests for Coeliac disease. Their bodies do not make the gluten antibodies that tTG IgA looks for even if they have Coeliac disease.
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