Acute Lymphocytic Leukemia (ALL)

Physicians perform an array of tests to help diagnose leukemia and determine its type and specific subtype. The tests help determine if there are changes in the amounts of different kinds of circulating blood cells, if the cells have an abnormal appearance when seen through a microscope, if there are changes in the cellular makeup of the bone marrow, to determine what changes have taken place in the genetic and molecular makeup of the diseased cells, and to discover any other factors that are helpful in deciding on the most effective course of treatment.

Blood tests can show whether the amounts of various components of blood are within normal ranges. In leukemia, red blood cell, platelet, and white blood cell levels may be diminished.

Bone marrow aspirates and biopsies are used to determine the number of blasts, or immature cells, in the marrow, and to uncover other features of the leukemic cells. Normally, blasts account for less than 5 percent of bone marrow content. In patients with leukemia, blasts increase to between 30 and 100 percent of marrow. In a bone marrow biopsy, physicians use a hollow needle inserted into the hipbone to remove a small piece of bone and marrow for examination. In a bone marrow aspirate, a small sample of liquid bone marrow is withdrawn through a syringe.

If diseased cells are found through the bone marrow biopsy or aspirate, physicians will also perform a lumbar puncture, or spinal tap, in which they take a sample of cerebrospinal fluid, which surrounds the brain and spinal cord -- the central nervous system (CNS), to see if the disease has spread there.

In addition, physicians use a number of tests that help them determine specific features of the cells in biopsied tissue including genetic abnormalities such as chromosomal rearrangements -- which are common in leukemias -- and whether the cells have specific proteins called antigens; this information helps both identify the cells' origins and determine the patient's prognosis. These tests include the following:

• Cytogenetic studies to determine chromosome changes in cells

• Immunohistochemistry studies, in which antibodies are used to distinguish between types of cancer cells

• flow cytometry, in which prepared cells are passed through a laser beam for analysis

• molecular genetic studies, highly sensitive DNA and RNA tests to determine specific genetic traits of cancer cells.

Physicians sometimes use imaging tests to determine whether ALL has affected the bones or the organs such as the kidneys or brain, or the lymph nodes. These tests can include chest x-rays, ultrasound, computed tomography (CT scan), and magnetic resonance imaging (MRI).