Acute Lymphocytic Leukemia

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Diagnosis & Tests

Physical examination shows enlarged liver and spleen, bruising (ecchymosis) and evidence of bleeding (petechiae, purpura, and so on).

• The WBC count is abnormal.
• A CBC shows anemia and low platelet count.
• A bone marrow aspiration shows an increased number of cells (hypercellularity) and an increase in lymphoblasts.

ALL may also alter the results of the following tests:

• T (thymus derived) lymphocyte count
• Cell surface antigen studies (B-cell, leukemia/lymphoma panel)
• White blood cell differential

Classification of ALL now depends on a number of specific sophisticated tests, such as immunophenotyping, karyotyping, and terminal deoxynucleotidyltransferase (TdT) activity. The combined results of these tests allows pinpoint molecular diagnosis, which helps guide the treatment decisions, and clarify the likely prognosis.

For instance, the cells of some leukemias contain chromosomal abnormalities. Those with the Philadelphia chromosome or with the t(4;11) translocation would tend to have a poor prognosis, thus intensive treatment and an early bone marrow transplant might be recommended preemptively. Other genes (such as the TEL/AML1 rearrangement) can indicate a very favorable prognosis.