What blood test examines the shape of red cells?

The blood test that examines the shape and size of red cells is called a peripheral blood smear. A peripheral blood smear is a thin layer of blood that is placed on a glass slide and then stained to make the red blood cells visible under a microscope. The shape and size of red blood cells can be affected by a variety of conditions, including anemia, sickle cell anemia, and thalassemia. A peripheral blood smear can also be used to detect other abnormalities, such as the presence of parasites or bacteria in the blood.