Does anyone know at what level a GP might consider MCV to be a problem and an indication of B12 deficiency? Mine is 99.8fl (80-99) which is marked as "abnormal" on my blood test results but the doctor never seems to mention it. As I have had fatigue for a few years I occasionally take B12 and folic acid even though my B12 result is always top end of normal. I was deficient in folic acid a couple of years ago but the GP gave me high dose folic acid and it now appears to be back to normal. Nothing has made me feel any better though.
I was on Tamoxifen for 5 years and am having a break to see if I feel any better not being on it, but sadly after 3 months I feel just the same so will probably start taking it again.
Any advice from you very knowledgeable people would be much appreciated.
Thank you
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flibertygibert
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If you supplement B12 then your serum level may very well show "normal" when, in fact, cellular levels are still low. High MCV can be due to low B12 but can also be caused by low Folate. All doctors will differ on what number they think is "abnormal" enough to search further and I have found some that are proactive and some that dismiss numbers that are way out of range. It is up to us as patients to keep pressing for answers if we feel that something needs addressing.
For me, the real answer was found by testing MMA (methylmalonic acid) and Hcy (homocysteine). If MMA is elevated then there is a good probability that you are functionally B12 deficient. Elevated Hcy can indicate a few different issues with low B12 and low Folate among the possibilities. I tested right in the middle of "normal" for serum B12 levels but, based on elevated MMA, Hcy, and Parietal Cell antibodies I have PA. The serum test was not an accurate indicator for me at all.
There are many more on this forum better educated than myself, hopefully they will offer you more information.
Hope you get solid answers to your health issues and that you are better soon!
Thank you for your response. I did have an MMA test a year ago and the results of that homocysteine were normal. Holotransobalamin was "above the upper limits of the reference range" so don't know what that means. Hopefully someone will have an idea and let me know.
tests have a limited range above and below which they just can't measure accurately - think of it a bit like having a meter rule as your only measuring stick - you can probably measure reasonably accurately for a 100 meters or so but you can't measure anything that is less than a meter and you wouldn't attempt to accurately measure anything over 100 meters.
If MMA and homocysteine are coming back and B12 is at top of range then its unlikely B12 is the problem - not impossible but extremely unlikely. Have other possibilities like thyroid been ruled out?
Yes, thyroid has also been checked and is absolutely fine too. It's weird as I seem to have all the symptoms of B12 deficiency but the results say otherwise.
Hi, I have PA, my diagnose was based on autoimmune atrophic gastritis, positive pareitial cell antibodies and anti intrinsic cell antibodies, not to mention a host of symptoms including MCV at 99. However my B12 was always in the normal range. Holotranscobolamin, MMA and Hcy have all come back normal, but these tests have always been done during supplementation of B12. The only thing that has improved the symptoms is self injecting. I've been keeping a journal and even at 3 injections a week the symptoms return. 4 to 5 injections per week keep me stable, no one can tell me why.
OK just refreshed my memory, high holotranscobolabim would seem to indicate sufficient B12 but it is not as sensitive as MMA which is the gold standard apparently. However, this information does not explain why people who have been diagnosed with PA, like myself, have normal levels when tested yet debilitating symptoms. B12 keeps me from sinking into depression (not to mention the extreme fatigue, insomnia, anxiety, breathlessness etc etc)
If you have BOTH low B12 AND iron deficiency, the MCV might not go as high as might otherwise be expected.
The low B12 tends to increase the size of red blood cells, the iron deficiency to reduce the size. Put the two together and you end up potentially with in-range MCV along with B12 deficiency and iron deficiency.
What can help identify that is a high Red-cell Distribution Width (RDW). If high, it indicates you have some small cells, some large. If low, it indicates cells of generally similar size.
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