I have Hashimoto’s and in the past tested low for vitamin d. I’ve been fatigued for many years and have had some mild memory issues. About 3 months ago I experienced sudden hair loss and testing showed my ferritin was quite low (14), thyroid was a bit off, and B12 was in the low end of the range. In addition to starting various supplements and tweaking my thyroid meds my doctor recommended starting on B12 injections.
All this is good, I think, but my doctor didn’t see any reason to do further testing to confirm PA. I would like to know one way or the other if possible so that I know whether I definitely need to continue with a lifetime of injections. So, now that my B12 level is sky high due to the injections is there any point in doing MMA testing or would the results be compromised? If compromised, how long would I need to wait after my last injection to get an accurate result? Also, how definitive is the MMA test? Will it tell me for certain whether I have PA?
Thanks in advance for the help!
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aggleflaggle1045
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You should not take any supplement with B12 before having your B12 assessed (including MMA/homocysteine/Active B12).
Methylmalonic acid is a chemical used up in one of the cellular reactions mediated by B12. If there's not enough B12 in the cell then MMA levels will rise. If they're not high then it means your cellular levels of B12 are OK. High levels of plasma MMA (>0.75umol/L0 almost invariably indicate cobamalin deficiency.
For testing intrinsic factor antibodies: keep one week between an injection and the test.
The IFA test is unreliable in that it gives false negatives in people with PA half the time. So a negative result doesn't mean that you don't have PA. However, a positive result is a sure-fire, 95% certain indicator of PA.
I am not a medically trained person but I've had Pernicious Anaemia (a form of B12 deficiency) for more than 46 years.
All an MMA test can tell you is that you might have a B12 deficiency. But you already know that you do.
B12 injections are for life unless the cause of the deficiency is definitely temporary or caused by diet. PA is not the only possible cause that requires injections for life. So, even if there was a way to tell, for sure, that you didn’t have PA you’d still probably need them forever.
Thanks for your quick responses and for the clarifications. This is all so complicated!
I think the reason I’m struggling to accept the need for lifetime injections is that my B12 tested at 257 pg/mL (211-911)—not at rock bottom like for so many on this forum. It makes me wonder if my symptoms are from my low ferritin and/or my thyroid being a bit off andnot due to low B12. And worry that I might end up having a lifetime of injections unnecessarily. It sounds like I can do the IFA testing and see how that turns out and, if negative, potentially discontinue the B12 supplementation someday and see what happens to my levels and symptoms. Right now I’m still waiting (hoping) for hair regrowth and am still quite fatigued. My iron is slowly creeping higher and we’re still tweaking my thyroid meds, so I wouldn’t want to discontinue the B12 at this point.
The IFA test is notoriously unreliable . You can often test negative and you can have PA .Also a high percentage of your B12 serum can consist of inactive B12 . So it could be risky for you to discontinue your B12 injections .
There aren't any good tests for PA at the moment. - to the extent that the BCSH standards refer to 'IFAB negative PA'. You might need to do the IFA test several times before you actually got a confirmatory positive.
PA is the most common cause of B12 absorption problems.
If you have hashis then there is somewhere between 10-40% probability of developing PA.
Easier to rule out other causes than confirm PA - you could look into h Pylori and/or SIBO (though there seems to be evidence to suggest that SIBO may be a precursor to PA).
Many on this sight haven't bothered to investigate exact cause but have assumed PA as trying to get an exact diagnosis is so difficult
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