In microcytic anemia, MCV < 80 fl. It may be accompanied by low MCH and MCHC and then is called microcytic hypochromic anemia. If one examines the peripheral blood film, microcytic cells are seen. Common clinical conditions where this is seen are Iron deficiency anemia and thalassemia. In macrocytic anemia on the other hand, MCV > 100fl. There is usually an increased MCH with a normal MCHC. Peripheral blood examination in such cases shows macrocytes.

Macrocytic anemia could be because of vitamin B12 and/or folic acid deficiency (then it is labelled as megaloblastic anemia) Or it could be due to other causes like liver disease, alcohol intake, hypothyroidism, aplastic anemia and accelerated erythropoiesis. Some drugs such as cytotoxic drugs, immunosuppressant and anticonvulsants can also cause macrocytic anemia.

In Normocytic anemia, the MCV is normal. These are usually accompanied by normal MCH and MCHC. There may be however a reduction in RBC Count. Peripheral blood film reveals relatively normal appearing red cells. Such anemia is found in chronic diseases and after acute blood loss.