How is aplastic anemia diagnosed?

Signs and symptoms of aplastic anemia

If you have aplastic anemia, you may have some of the following problems:

• Feeling very tired (fatigued) and short of breath, which is caused by anemia (too few red blood cells). People with anemia also tend to be pale.
• Problems with infections that keep coming back or are severe (even life-threatening). This is caused by not having enough infection-fighting white blood cells (called neutropenia/leukopenia)
• Abnormal bruising or bleeding because of a shortage of platelets (thrombocytopenia)

Some people may not have any symptoms, but results of a routine blood test may suggest a diagnosis of aplastic anemia. There are other conditions in which blood formation may be abnormal. Your doctor will consider all of these when determining your diagnosis.

Tests to diagnose aplastic anemia

Two main tests are used to diagnose aplastic anemia.

• Complete blood count (commonly called a CBC). In aplastic anemia this test will show that the red cell count, white cell count, and platelet count are low.
• Bone marrow biopsy. This test looks at the bone marrow, which contains the blood-forming cells.

Complete blood count

The complete blood count (CBC) is a test that measures the different cells in the blood, such as the red blood cells, the white blood cells, and the platelets. This test is done on a sample of blood, usually taken from a vein in your arm.

If this test shows that your blood counts are low, other tests may be done to look for the cause. Often the levels of vitamins (like vitamin B12 and folate) and iron will be checked to be sure that low levels aren’t causing the low blood counts. Poor kidney function can sometimes cause anemia, so blood chemistry tests are often checked as well.

If these tests do not find an underlying cause of the low blood counts, you will need to have a bone marrow biopsy.

You can learn more about blood tests that are commonly used in our document Understanding Your Lab Test Results.

Bone marrow biopsy

A bone marrow biopsy has 2 parts: the aspiration and the biopsy. This procedure is usually done while you are lying on your stomach. A part of the pelvic bone (located about 2 inches to the side of the spine) and the skin above it are numbed with local anesthetic. A tiny cut (about 1/8 inch) may be made in the skin to make it easier to insert the needle. Then, for the aspiration, a large needle is placed through the incision into the bone. A syringe is used to remove a small amount of liquid bone marrow (about 1 teaspoon). Even with the numbing medicine, this often causes a brief, sharp pain.

For the biopsy, the needle is repositioned and used to remove a small cylinder-shaped piece of bone and marrow (about 1/16 inch in diameter and 1/3 inch long). Both samples usually are taken during the same procedure from the same place in the back of the pelvic (hip) bone. In spite of local anesthesia, this procedure may still be uncomfortable.

A pathologist, a doctor specializing in diagnosing disease by lab tests, examines the bone marrow under a microscope. A hematologist (internist who specializes in blood diseases) or a hematopathologist (a pathologist who specializes in blood diseases) might also look at the bone marrow sample. Normally, the bone marrow contains many cells that produce the different types of blood cells. Finding an “empty” bone marrow -- that is, one that lacks normal blood-producing cells -- confirms the diagnosis of aplastic anemia. Leukemia or other kinds of cancers can also cause low blood counts, but in that case the bone marrow would be filled with leukemia cells or other cancer cells.