According to Medscape, some of the most common reasons why MCV would be high in a blood test include liver disease, anemia, excessive alcohol intake, hypothyroidism and myelodysplastic syndrome. Each of these conditions and diseases will make the volume of red blood cells in the blood stream rise.
MCV stands for either mean cell volume or mean corpuscular volume. This is a measurement of the average volume of red blood cells exist in the bloodstream. The measurement can be taken directly using an automated hematology analyzer, or it can be accurately calculated using a mathematical formula based off of the red blood cell count and hematocrit. The MCV is used most often when discussing individuals who have anemia. Macrocytic anemia means that the MCV is above average, normocytic anemia means that the MCV is normal and microcytic anemia indicates a below-average MCV.
The Medscape website indicates that there are several other conditions and diseases other than anemia that would make the mean corpuscular volume higher than a desired amount, some of which include vitamin B12 and folate deficiencies, excessive alcohol use or hypothyroid. A high MCV is a sign of a health risk that could be severe, which means that if a patient has a high MCV, the health care professional should do test to find out what is causing such a high volume.