A diagnosis of anemia is most often determined with a complete blood count test, which allows a physician to measure the amount of red blood cells and hemoglobin in the blood, states the Mayo Clinic. Sometimes, a sample of bone marrow is required for an anemia diagnosis.
Additionally, a physical exam and a test that shows the size and shape of blood cells is sometimes required, explains the Mayo Clinic. Anemia that is caused by an iron deficiency may require additional tests, as this condition can result from a wide array of health issues such as ulcers, colon cancer, tumors and kidney polyps. Anemia occurs when the body doesn't make enough red blood cells, the body destroys red blood cells or bleeding causes red blood cell loss faster than red blood cells are made.
There are multiple types of anemia, such as vitamin deficiency anemia, aplastic anemia, anemia of chronic disease, sickle cell anemia, hemolytic anemia and anemias associated with bone marrow disease, according to the Mayo Clinic. Additionally, there are some types of anemia that are not as common, such as thalassemia and anemias that result from defective hemoglobin. Red blood cells, which contain hemoglobin, are responsible for carrying oxygen throughout the body and carrying carbon dioxide to the lungs, where it is exhaled. The body requires iron for hemoglobin production.