Quote:
Originally Posted by mrsD
One misconception doctors still have is that anemia must be present to have a real deficiency. This has been shown in papers to not be the case. Sometimes one blood test will hint at low B12 before anemia becomes severe, and that is MCV.
But many people can be low and not anemic.
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This is an important point. Mean corpuscular volume (MCV) is a measurement of the average size of your red blood cells (RBCs). The MCV is elevated when your RBCs are larger than normal (macrocytic), for example in people with vitamin B12 deficiency. My MCV has been on the high side during my last three physicals and only the doctor during my last physical noticed this, retrospectively after seeing my very low B12 count. I'm not anaemic but I do have neurological issues - my consistently elevated MCV should have been a red flag given my neurological issues.
MCV is a test which is routinely done as part of your CBC (complete blood count) and if the number is too high or too low, it is an indication that further testing might be required. When the MCV is decreased, your RBCs are smaller than normal (microcytic) as is seen in iron deficiency anemia or thalassemias.