How Is Anemia Diagnosed?

Anemia is diagnosed using a person’s medical history, a physical exam, and tests. Your doctor can use these methods to determine the cause, severity, and treatment for the particular type of anemia you may have. Mild to moderate anemia may have no symptoms or very mild symptoms. In fact, anemia is often discovered unexpectedly on blood tests looking for other conditions.

Medical and Family History

Your doctor may ask detailed questions about many symptoms common to anemia, including feeling tired and weak. You may be asked if you’ve had an illness or condition that could cause anemia and whether you are taking medicines that could cause anemia. Your doctor may ask about your diet and whether you have family members who have anemia or a history of anemia.

Physical Exam

Your doctor will do a physical exam to determine how severe the anemia is and to check for possible causes. This exam may include listening to the heart for a rapid or irregular heartbeat, listening to the lungs for rapid or uneven breathing, or feeling the abdomen to check the size of your liver and spleen. The doctor may perform a pelvic or rectal exam to check for common sources of blood loss.

Diagnostic Tests and Procedures

Your doctor may order various tests or procedures to determine the type and severity of anemia you have. Usually, the first test used to diagnose anemia is a complete blood count (CBC). The CBC tells a number of things about a person’s blood, including:

• The hemoglobin level. Hemoglobin is the iron-rich protein in red blood cells (RBCs) that carries oxygen through the body. The normal range of hemoglobin levels for the general population is 11–15 g/dL. A low hemoglobin level means a person has anemia.
• The hematocrit (hee-MAT-oh-crit) level. The hematocrit level measures how much of the blood is made up of RBCs. The normal range for hematocrit levels for the general population is 32–43 percent. A low hematocrit level is another sign of anemia.

The normal range of these levels may be lower in certain racial and ethnic populations. Your doctor can explain your individual test results.

The CBC also checks:

• The number of RBCs. Too few RBCs means a person has anemia. A low number of RBCs is usually seen with either a low hemoglobin or a low hematocrit level, or both.
• The number of white blood cells. White blood cells are involved in fighting infection.
• The number of platelets in the blood. Platelets are small cell fragments that are involved in blood clotting.
• RBC size. The mean cell volume measures the average size (volume) of RBCs. In iron deficiency anemia, the RBCs are usually smaller than normal. This is called microcytosis (MIKE-ro-si-TO-sis).

If the CBC results confirm that you have anemia, your doctor may order additional tests to determine the cause, severity, and correct treatment for your condition. Some of the tests may include:

• Hemoglobin electrophoresis (e-lek-tro-FOR-e-sis). This test evaluates the different types of hemoglobin in the blood. The hemoglobin electrophoresis test is used to diagnose types of anemia caused by abnormal hemoglobin in the RBCs.
• Reticulocyte (re-TIK-u-lo-site) count. Reticulocytes are young RBCs. This test measures the number of new RBCs in your blood. The reticulocyte test is used to determine whether your bone marrow is producing RBCs at the proper rate. A higher than average count usually indicates either blood loss or destruction of RBCs earlier than their normal life of 120 days. A lower than average count indicates a decreased production of RBCs by the bone marrow. People with pernicious anemia have low reticulocyte levels.

Several tests can be used to check the level of iron in your blood and body. These tests include serum iron, serum ferritin, transferrin level, or total iron-binding capacity. Because anemia has many causes, the doctor may order tests for conditions such as kidney failure, lead poisoning (in children), and deficiencies of vitamins (B12, folate).

If your doctor suspects that you have anemia because of internal bleeding in your stomach or intestines, several tests may be used to discover the source of the bleeding. A test to check the stool for blood may be done in the doctor’s office. Your doctor can give you a kit to help you obtain a sample at home. Your doctor will instruct you to bring the sample back to his or her office or send it to a lab.

If blood is found in the stool, additional tests may be used to find the source of the bleeding. One such test is endoscopy. In this test, a tube with a tiny camera is used to view the lining of the digestive tract.

In some cases, your doctor may want to do a bone marrow aspiration or biopsy. A bone marrow biopsy is a minor surgical procedure to remove a small amount of bone marrow tissue. Bone marrow aspiration or biopsy test whether your bone marrow is healthy and making enough blood cells. For a bone marrow aspiration, your doctor removes a small amount of bone marrow fluid through a needle.