Your doctor will diagnose iron-deficiency anemia based on your medical history, a physical exam, and the results from tests and procedures.
                
Once your doctor knows the cause and severity of the condition, he or she can create a treatment plan for you.
                
Mild to moderate iron-deficiency anemia may have no signs or symptoms. Thus, you may not know you have it unless your doctor discovers it from a screening test or while checking for other problems.
                
Specialists Involved
                
Primary care doctors often diagnose and treat iron-deficiency anemia. These doctors include pediatricians, family doctors, gynecologists/obstetricians, and internal medicine specialists.
                
A hematologist (a blood disease specialist), a gastroenterologist (a digestive system specialist), and other specialists also may help treat iron-deficiency anemia.
                
Medical History
                
Your doctor will ask about your signs and symptoms and any past problems you've had with anemia or low iron. He or she also may ask about your diet and whether you're taking any medicines.
                
If you're a woman, your doctor may ask whether you might be pregnant.
                
Physical Exam
                
Your doctor will do a physical exam to look for signs of iron-deficiency anemia. He or she may:
                
Look at your skin, gums, and nail beds to see whether they're pale
                
Listen to your heart for rapid or irregular heartbeats
                
Listen to your lungs for rapid or uneven breathing
                
Feel your abdomen to check the size of your liver and spleen
                
Do a pelvic and rectal exam to check for internal bleeding
                
Diagnostic Tests and Procedures
                
Many tests and procedures are used to diagnose iron-deficiency anemia. They can help confirm a diagnosis, look for a cause, and find out how severe the condition is.
                
Complete Blood Count
                
Often, the first test used to diagnose anemia is a complete blood count (CBC). The CBC measures many parts of your blood.
                
This test checks your hemoglobin and hematocrit (hee-MAT-oh-crit) levels. Hemoglobin is an iron-rich protein in red blood cells that carries oxygen to the body. Hematocrit is a measure of how much space red blood cells take up in your blood. A low level of hemoglobin or hematocrit is a sign of anemia.
                
The normal range of these levels varies in certain racial and ethnic populations. Your doctor can explain your test results to you.
                
The CBC also checks the number of red blood cells, white blood cells, and platelets in your blood. Abnormal results may be a sign of infection, a blood disorder, or another condition.
                
Finally, the CBC looks at mean corpuscular (kor-PUS-kyu-lar) volume (MCV). MCV is a measure of the average size of your red blood cells. The results may be a clue as to the cause of your anemia. In iron-deficiency anemia, for example, red blood cells usually are smaller than normal.
                
Other Blood Tests
                
If the CBC results confirm you have anemia, you may need other blood tests to find out what's causing the condition, how severe it is, and the best way to treat it.
                
Reticulocyte count. This test measures the number of reticulocytes (re-TIK-u-lo-sites) in your blood. Reticulocytes are young, immature red blood cells. Over time, reticulocytes become mature red blood cells that carry oxygen throughout your body.
                
A reticulocyte count shows whether your bone marrow is making red blood cells at the correct rate.
                
Peripheral smear. For this test, a sample of your blood is examined under a microscope. If you have iron-deficiency anemia, your red blood cells will look smaller and paler than normal.
                
Tests to measure iron levels. These tests can show how much iron has been used from your body's stored iron. Tests to measure iron levels include:
                
Serum iron. This test measures the amount of iron in your blood. The level of iron in your blood may be normal even if the total amount of iron in your body is low. For this reason, other iron tests also are done.
                
Serum ferritin. Ferritin is a protein that helps store iron in your body. A measure of this protein helps your doctor find out how much of your body's stored iron has been used.
                
Transferrin level, or total iron-binding capacity. Transferrin is a protein that carries iron in your blood. Total iron-binding capacity measures how much of the transferrin in your blood isn't carrying iron. If you have iron-deficiency anemia, you'll have a high level of transferrin that has no iron.
                
Other tests. Your doctor also may recommend tests to check your hormone levels, especially your thyroid hormone. You also may have a blood test for a chemical called erythrocyte protoporphyrin. This chemical is a building block for hemoglobin.
                
Children also may be tested for the level of lead in their blood. Lead can make it hard for the body to produce hemoglobin.
                
Tests and Procedures for Gastrointestinal Blood Loss
                
To check whether internal bleeding is causing your iron-deficiency anemia, your doctor may suggest a fecal occult blood test. This test looks for blood in the stools and can detect bleeding in the intestines.
                
If the test finds blood, you may have other tests and procedures to find the exact spot of the bleeding. These tests and procedures may look for bleeding in the stomach, upper intestines, colon, or pelvic organs.