I had low b12, at 156. They gave me the injection. About an hour later they drew my blood and I was pos for IFA but neg for PA. I had an endoscopy and had no atrophic gastritis, so was given another IF test and this time was neg.
Went to a new Dr and she gave me a b12 shot, and about 45 minutes later, I had my blood drawn to take another IF test. This time I was positive at 17. now I am wondering if I could have had false positives because they were so close to receiving injections. I wonder if it would be worth it for me to try to take another one in a few weeks
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I think you've answered your own question here. I'm puzzled why they would give you an injection before drawing blood for tests, to be honest. A repeat test after a few weeks of no treatment would clinch it for you.
When you say you were positive for IFab but negative for PA, how was pernicious anaemia tested for ?
A positive IFab test result is used to confirm PA. A single negative IFab test result cannot rule it out, as the test will only pick up about 40-60% of those with PA. Antibodies to intrinsic factor need to be active when testing to be identified. So it is possible to have a few negative results before getting a positive - which is 95% accurate, and so would confirm PA.
Having said that, I think you and Flipper are right - that the B12 injection prior to testing is possibly causing a false positive. Worth another test ?
I often wonder if it’s worth worrying about false positives. You’d only be having the test because of B12 deficiency anyway, and they’re all treated the same way….so a positive IFAB, even if it’s “false” because of a recent injection, is helpful in the long run for getting injections yes?
Depends if you really want to know the cause of your B12 deficiency - or really want to ring-fence your B12 injections.
I don't think you can have been "neg for PA", by the way - since there is no gold standard test for diagnosing pernicious anaemia.
I have had three negative IFab tests - done despite having already had a confirmed diagnosis of functional B12 deficiency. However, practically all my family have autoimmune conditions: Grave's disease (autoimmune thyroid), vitiligo, psoriasis .... and two have B12 deficiency (cause not known). One of my sisters has to have immunosuppressants.
So who knows ?
In some ways though, the cause makes little difference to me: I self inject twice a week, which mainly works for me. Just as I need to apply nipple cream twice a day to manage my angular cheilitis (split, sore and bleeding mouth), otherwise it returns within days.
It’s important to know because once your b12 gets to a level that is “within range” (don’t get me started 😡), they will discontinue injections and then you could be back to square one within a matter on weeks or months. If you have the diagnosis, it’s injections for life.
Hi, by 'neg for PA' would you be meaning anti parietal cell antibodies or pernicious anaemia (which doesn't have a test other than IFab as far as I know, even though it only shows as +ve in about half of those with pernicious anaemia) Cheers
As a vegan I was intrigued by your profile name so I wonder if you are vegetarian or vegan? B12 absorption issues including PA can of course happen regardless of diet but vegans need to add B12 to their diet via fortified foods or taking a regular supplement (at the right dose). Vegetarians might also run a bit low depending on diet and supplementation choices.
The right type if B12 in supplements is a complex issue. Some things like spirulina are supposed to provide B12 but turns out it is a form incompatable with human digestion. Please research this issue thoroughly as symptoms of B12 def. can take years to manifest and can even result in heart attacks before other symptoms show up. As ever life is complex!
I'm not sure if you intended to reply to me or the original poster. I would never recommend spirulina as a source of B12, since as you alluded to, it likely contains analogs rather than viable human-usable B12.
B12 supplements from a reputable manufacturer should be reliable but it's a good idea to have several different sources in case of an issue with any single source. Reputable B12 supplement manufacturers do not use B12 analogs in their products. The type of B12 (cyano, methyl, adenosyl, hydroxo) is another discussion but all forms will "work".
Perhaps you have not read my profile or posts before but asking me to research B12 deficiency or B12 supplements thoroughly is shall we say.... err a little strange.
So sorry Technoid you obviously know what you are doing. I just worry that people are getting in to hot water thinking they are getting B12 from the right vegetarian/vegan source. I should've have realised everyone here is clued up. Sorry again🙄xx
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