How Is Aplastic Anemia Diagnosed?

Aplastic anemia is diagnosed using a medical and family history, a physical exam, and tests to discover the type and cause of anemia. Your doctor can use these methods to find out how severe the anemia is and to decide the appropriate treatment.

Specialists Involved

A person with suspected aplastic anemia may be referred to a hematologist (an expert in treating blood conditions).

Medical and Family History

During a medical history, your doctor may ask detailed questions about many kinds of symptoms. He or she may ask if you have ever had problems with anemia, had an illness or condition that could cause anemia, or been exposed to drugs, chemicals, or radiation. The doctor will ask about medicines you are taking to see if they might be a cause of the anemia. The doctor will also ask if your family members have ever had any kind of anemia.

Physical Exam

Your doctor will do a physical exam to see how severe the anemia is and to check for its possible causes. This exam may include:

• Checking for pale or yellowish skin
• Listening to the heart for rapid or irregular heartbeats
• Listening to the lungs for rapid or uneven breathing
• Feeling the abdomen to check the size of the liver and spleen and checking for swelling in the legs
• Checking for signs of bleeding

Diagnostic Tests and Procedures

Several tests of the blood and bone marrow may be used to diagnose aplastic anemia. The reasons for testing are to:

• Confirm a diagnosis of aplastic anemia and look for its cause
• Rule out blood cancers that can cause bone marrow failure
• Determine the severity of the aplastic anemia
• Check for the presence of paroxysmal nocturnal hemoglobinuria

Complete Blood Count

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 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 red blood cells. 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 red blood cells. Too few red blood cells means a person has anemia. A low number of red blood cells 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.
• Red blood cell size. The mean cell volume measures the average size (volume) of red blood cells.

Reticulocyte Count

This test measures the number of new red blood cells in the blood. It helps doctors find out whether bone marrow is producing red blood cells at the proper rate. A lower than average level can mean that the bone marrow is not making enough red blood cells. The reticulocyte (re-TIK-u-lo-site) level is low in people with aplastic anemia.

Bone Marrow Tests

This test looks at the bone marrow to see if it is healthy and if it is making enough blood cells. A small amount of bone marrow may be removed and examined. Removing a small bit of liquid bone marrow is called aspiration. Removing bone marrow tissue is called biopsy.

A bone marrow aspiration may be done to find what is causing the low production of blood cells. Since blood cells are formed inside the bones, doctors use a needle to remove a small amount of liquid bone marrow. The sample is then examined under a microscope to check for abnormal cells.

A bone marrow biopsy is usually done at the same time, especially if an aspiration was not productive. A small number of bone marrow cells with a small piece of bone is removed using a needle. This test checks the number and type of cells in the bone marrow. In aplastic anemia, the bone marrow has a lower than normal number of cells.

Other Tests

Additional tests may be used to help diagnose aplastic anemia, including:

• X ray, CT scan, or ultrasound of the abdomen to look for an enlarged spleen or lymph nodes, which could indicate blood cancer. These tests also may be used to examine the kidneys, arms, and hands, which are sometimes abnormal in young people with Fanconi anemia.
• Chest x ray to provide a picture of the heart and lungs and rule out infection.
• Liver tests and viral studies to check for hepatitis and viruses.
• Tests that check vitamin B12 and folate levels to rule out anemia due to vitamin deficiency.
• Blood tests for paroxysmal nocturnal hemoglobinuria and to check the immune system for antibodies.