MCV (mean corpuscular volume) and MCH (mean corpuscular hemoglobin) levels are tested as part of a CBC, or a complete blood count test. The MCV test measures the size of the average red blood cell. The MCH test measures the amount of hemoglobin in the average red blood cell. Hemoglobin is the substance that carries oxygen to the body's cells. These two tests correlate because large red blood cells, as indicated by a high MCV number typically have a larger amount of hemoglobin than do normal-sized red blood cells. Thus a high MCV result typically leads to an MCH total that is also high.
Normal MCV levels are generally between 80 and 100, and normal MCH levels are between 27 and 31. Large blood cells found with high MCV totals are called macrocytic. Red blood cells with abnormally high hemoglobin levels as indicated by a high MCH are called hyperchromic. In addition to folic acid or vitamin B12 deficiency, chemotherapy sometimes causes high MCV and MCH levels.Learn more about Medical Ranges & Levels