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Acute Lymphocytic Leukemia

Description

An in-depth report on the causes, diagnosis, treatment, and prevention of leukemia.

Alternative Names

Acute Lymphoblastic (or Lymphocytic) Leukemia

Diagnosis

Laboratory tests provide the basis for diagnosing ALL.

Flow Cytometry

Flow cytometry is an important diagnostic technique in leukemia that uses complex fluids, laser optics, and computers. It is most often used to count blood cells but it can also determine the components and structural features of cells. It can process thousands of cells in seconds and take measurements of a single cell. Advanced techniques using flow cytometry employ fluorescent light that is scattered by cells and revealed by lasers. The features of the scattered light allow experts to detect many characteristics of the cells. It is important in leukemia for diagnosing patients, for providing information on their prognosis, and for identifying residual disease after treatments.

Complete Blood Cell Count

A complete blood cell count is the first step in diagnosing ALL. This test will often show various findings, including the following:

  • The presence of circulatory leukemic blast cells.
  • The presence and severity of anemia.
  • The count of a variety of blood cell types. (A high white blood cell count indicates a more severe disease.)
  • These tests will not always show the presence of leukemic cells.
Complete blood count - series Click the icon to see an illustrated series detailing a complete blood cell count test.

Blood tests do not always detect leukemia, and about 10% of patients with ALL have a normal blood cell count.

Bone Marrow Biopsy

If the results of the blood tests are abnormal or the physician suspects leukemia despite normal cell counts, a bone marrow aspiration and biopsy are the next steps.

  • A local anesthetic is given. (This is a very common and safe procedure. However, because this test can produce considerable anxiety, particularly in children, parents may want to ask the physician if sedation is appropriate for their child.)
  • A needle is inserted into the bone, usually the rear hipbone. There may be brief pressure or pain. A small amount of marrow is withdrawn. (It looks like blood.)
  • A larger needle is then inserted into the same place and pushed down to the bone. The health professional will wiggle the needle from side to side to loosen a larger specimen for the biopsy. The patient will feel some pressure.
  • The sample is then taken to the lab to be analyzed. All the results are completed within a couple of days.
Bone marrow aspiration Click the icon to see an image of bone marrow removal.

Normal bone marrow contains 5% or less blast cells (the immature cells that ordinarily develop into healthy blood cells). In leukemia, abnormal blasts constitute between 30% and 100% of the marrow.

Spinal Tap

If bone marrow examination confirms ALL, a spinal tap may be performed, which uses a needle inserted in to the spinal canal. The patient feels some pressure and usually must lie flat for about an hour afterward to prevent severe headache. This can be difficult, particularly for children, so parents should plan reading or other quit activities that will divert the child during that time. Parents should also be certain that the professional administering this test is highly experienced.

Lumbar puncture (spinal tap) Click the icon to see an image of a spinal tap.

A sample of cerebrospinal fluid with leukemia cells is a sign that the disease has spread to the central nervous system. In most cases of childhood ALL, leukemic cells are not found in the cerebrospinal fluid.

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