The single most useful erythrocyte index in the evaluation of anemia.
An increased mean corpuscular volume may reflect increased reticulocytosis from bleeding or hemolysis, liver disease, alcohol toxicity, HIV infection, chemotherapy, vitamin B12 or folate deficiency.
A decreased mean corpuscular volume indicates, iron deficiency, thalassemia, sideroblastic anemia, or chronic inflammatory disease.
Liver disease can lead to the formation of target cells which can increase the MCV.
Chronic inflammation and sideroblastic anemia almost never present within MCV below 70 fl.
An elevation of the MCV above 94fl can identify 34% of woman and 62% of all women with hemachromatosis.
The mean corpuscular volume in iron deficiency rarely falls below 80 fl until the hematocrit is well below 30 and the red blood cell count is less than 4 million.
In thalassemia the MCV is disproportionately low for the degree of anemia.
Mentzer index: It is a mean corpuscular volume divided by red blood cell count.