A peripheral smear involves looking at a blood sample under a microscope to determine cell size and shape. The hematocrit and hemoglobin tests indicate the oxygen-carrying capacity of red blood cells. For more information, see the article Blood Tests in the December 1996 BETA . In some cases, a bone marrow biopsy is done to look for stem cells and precursor blood cells. The Basics Red blood cells, also known as erythrocytes, are the most abundant type of blood cell.
Anemia refers to a low hemoglobin level or a low number of properly functioning red blood cells.
Red blood cells are responsible for picking up oxygen in the lungs and transporting it to the body's tissues. These cells contain hemoglobin, a red pigment that gives blood its color and enables the cells to carry oxygen. The heart also works harder to circulate more blood and thus more oxygen. When this happens, the heart has little reserve capacity to handle exertion, and people with anemia may feel short of breath when exercising. When the hemoglobin level is severely reduced, people may experience shortness of breath even while at rest.