Mean corpuscular volume (MCV) TEST

Mean corpuscular volume (MCV) is a value calculated during a routine blood test called a complete blood count (CBC). MCV measures the average size of your red blood cells. Your red blood cells carry oxygen throughout your body. This oxygen, in turn, powers your cells. The characteristics of your red blood cells — including size — provide information about how successfully they can transport oxygen. An MCV blood test is helpful because having a large number of atypically large or atypically small red blood cells can indicate certain conditions. It’s less helpful if you have a wide variety of red blood cell sizes in a blood sample. In that case, even if there’s an abnormality, the numbers may average out as normal. An MCV is routinely performed by an automated machine on all CBCs. It’s included in the portion of the CBC that provides information on your red blood cells in particular, called the RBC (red blood cell) indices.