ON THIS PAGE: You will find a list of the common tests, procedures, and scans that doctors can use to find out what’s wrong and identify the cause of the problem. To see other pages, use the menu on the side of your screen.
Doctors use many tests to diagnose leukemia and determine if it has spread to another part of the body, called metastasis. Some tests may also determine which treatments may be the most effective. A patient history, physical examination, complete blood cell count (CBC), and bone marrow aspiration (see below) are the main procedures used to diagnose ALL or rule out other conditions.
Blood tests . A CBC provides a count of each type of cell in the blood. The blood count may also show abnormal leukemia cells. The blood count is abnormal, in some way, for nearly all children with ALL when they are diagnosed. A blood chemistry test gives information about the body’s kidney and liver function, as well as other measures, such as salt levels.
Bone marrow aspiration and biopsy . These two procedures are similar and often done at the same time to examine the bone marrow. Bone marrow has both a solid and a liquid part. A bone marrow aspiration removes a sample of the fluid with a needle. A bone marrow biopsy is the removal of a small amount of solid tissue using a needle. A pathologist then analyzes the sample(s). A common site for a bone marrow aspiration and biopsy is the pelvic bone, which is located in the lower back by the hip. The skin in that area is usually numbed with medication beforehand, and other types of anesthesia (medication to block the awareness of pain) may be used.
A bone marrow aspiration is recommended if the blood test shows unusual blood counts or immature cells, or if the doctor suspects that a child may have leukemia. From this test, the doctor can find out whether the child has leukemia and, if so, what type of leukemia it is. The doctor or nurse will collect more than one sample of bone marrow at the same time for other tests, such as chromosome and molecular genetic tests and immunophenotyping (see Classification ). These additional tests are important to plan the most appropriate treatments.
Lumbar puncture (spinal tap). A lumbar puncture can determine if the leukemia has spread to the cerebral spinal fluid (CSF). CSF is the fluid that flows around the brain and the spinal cord. During a lumbar puncture, the doctor uses a needle to take a sample of the CSF to look for leukemia cells. Doctors may give an anesthetic to numb the lower back before the procedure and/or use anesthesia to block awareness of the pain. Knowing whether or not there is leukemia in the central nervous system helps doctors choose the most appropriate treatment. All children with ALL receive medicine to treat or prevent leukemia of the central nervous system at the same time as the lumbar puncture at specific times during treatment.
After diagnostic tests are done, your child’s doctor will review all of the results with you. If the diagnosis is ALL, these results also help the doctor describe the disease; this is called classification . Learn more about the first steps to take after a diagnosis of leukemia .
The next section in this guide is Classification,  and it explains the system doctors use to describe the extent of the disease. Or, use the menu on the side of your screen to choose another section to continue reading this guide.