If you have iron-deficiency anemia, it means your red blood cells are not carrying enough oxygen to the cells in your body. Iron deficiency makes it hard for your body to make the protein hemoglobin. Your red blood cells need hemoglobin to carry oxygen. Iron-deficiency anemia is the most common type of anemia. It can cause symptoms like fatigue, shortness of breath, headaches, cold hands and feet, and dizziness. Iron-deficiency anemia may also be a warning sign of other serious medical problems like bleeding or a problem with digestion. But early and mild iron-deficiency anemia may have no signs or symptoms, so how do doctors diagnose it? Testing for Iron-Deficiency Anemia Blood tests can show iron-deficiency anemia before symptoms develop. These tests include a complete blood count, which will measure your hemoglobin level. Iron-deficiency anemia makes your red blood cells appear smaller under a microscope. Blood tests can also measure the amount of iron in your blood and the amount stored in your body. Testing Without Symptoms Doctors test for iron-deficiency anemia in all pregnant women. Pregnancy increases the demand for iron. Iron-deficiency anemia during pregnancy can lead to problems with pregnancy and problems for a developing baby. Doctors also check hemoglobin levels in all children at age one. If you are not pregnant and not a child, your doctor may still test you for iron-deficiency anemia if you are at increased risk. Here are some conditions that increase your risk of developing iron-deficiency anemia: You are a woman with heavy menstrual periods. You are breastfeeding. You have a condition that interferes with your digestion. You have a condition that causes bleeding such as an ulcer. You are a vegetarian. Testing With Symptoms If you have signs and symptoms of iron-deficiency anemia, your doctor will use the same tests to diagnose you. Along with common symptoms, your doctor may suspect iron deficiency if you have signs of anemia during a physical exam. These signs include: Irregular heartbeat or heart sounds Pale color of skin, gums or nail beds An enlarged spleen or liver Brittle nails or hair loss Testing After Diagnosis If your doctor diagnoses iron-deficiency anemia with blood tests, more tests may be necessary. Your doctor will want to find out what is causing your anemia. Additional tests may include: Checking your stool and urine for blood Doing imaging studies to look for sources of bleeding Doing a procedure (endoscopy) to look into your digestive tract Doing other blood studies to look for diseases that cause abnormal hemoglobin (such as thalassemia and sickle cell disease) An iron-rich diet and iron supplements can help replenish iron and eliminate your symptoms, but you may need additional treatments depending on the underlying cause. For instance, if you have a stomach ulcer, your doctor can prescribe medication and perform endoscopy to stop any bleeding.