Tests That Help Evaluate Acute Myeloid Leukemia
Your doctor will request other tests to learn more about your specific type of leukemia. These will also help find out if the leukemia is causing any other problems in your body. It is important for your doctor to know these things so that he or she can decide on the most effective types of treatment for you. In addition to a history, physical exam, bone marrow biopsy, and blood tests, you may need one or more of these tests:
Your doctor may order a chest X-ray to make a picture of the organs and lymph nodes inside your chest. This test cannot show leukemia cells, but it can show if you have an infection in your lungs resulting from your leukemia. It can also help your doctor see if lymph nodes in this area are swollen. The test only takes a few minutes and it won't cause any pain.
This test is not always done. Your doctor may order it if you have symptoms involving your central nervous system. Doctors use this test to find out if leukemia cells have spread to your brain or spinal cord. This is more likely to be the case with a monocytic subtype of acute myeloid leukemia (AML) or if your blood count is high at the time of diagnosis.
Your doctor first numbs the area around your lower back with a local anesthetic. Then he or she inserts a needle into the spinal cavity near your spinal cord to remove cerebrospinal fluid. Even with the anesthesia, you may feel brief pain while the needle is inserted. The entire procedure takes only about 10 to 20 minutes. Your doctor sends the removed fluid to a lab where a pathologist checks for leukemia cells under a microscope.
This procedure uses sound waves to create moving images of your heart. Your doctor will use these images to check how well your heart is pumping. You may need this test if you are going to take certain chemotherapy drugs that have side effects on the heart.
Magnetic resonance imaging (MRI)
Doctors do not commonly order MRIs for AML. However, if you have symptoms such as back pain or weakness in your legs, your doctor may recommend an MRI to check your spine. The test may also help determine if leukemia has spread to your chest or brain. If so, the MRI can reveal the size and extent of the spread. MRIs may also be helpful if the results of an X-ray or CT scan aren't clear. MRIs use radio waves and magnetic fields to create detailed pictures of the inside of your body. In some cases, you are injected with a contrast dye about 30 to 60 minutes before getting the scan. For this test, you lie still on a table as it passes through a tubelike scanner. Then the scanner rotates around you. A computer uses data from radio waves to create pictures of the inside of your body. You may need more than one set of images, and each one may take 2 to 15 minutes. This test is painless and noninvasive. Ask for earplugs to help block out the loud thumping noise during the scan. If you are claustrophobic, you may be given a sedative before having this test.
Your doctor may use this test to determine if any lymph nodes or organs in your body are enlarged. It isn't often needed to diagnose AML, but it may be done if your doctor thinks the leukemia may be growing in an organ, like your spleen. CT scans use X-rays directed at the body from several angles to create detailed pictures of the inside of your body. Before the test, you may be asked to drink a contrast solution or get an IV injection of a contrast dye that helps better outline abnormal areas in the body. Some people may have allergic reactions to the contrast. For the test itself, you lie on a table that slides in and out of the scanner while the images are created. This test takes a bit longer than a standard X-ray.
Molecular genetic tests
Sensitive lab tests, such as polymerase chain reaction (PCR) and fluorescence in situ hybridization (FISH), can be used on samples of your blood or bone marrow to look for leukemia cells and help determine what type of leukemia you have. These tests may also be used after the first phase of treatment to detect any remaining leukemia cells. They can detect even very small amounts of disease.