Diagnosis of Chronic Myelogenous Leukemia

Diagnostic Evaluation of Chronic Myelogenous Leukemia

Physical Examination

The first step in the diagnosis of chronic myelogenous leukemia (CML) is a thorough medical history followed by a physical examination.

  • The most common symptom of chronic myelogenous leukemia discovered on physical examination is splenomegaly (enlargement of the spleen).

  • About 15% of patients also have hepatomegaly (enlargement of the liver).

  • As mentioned previously, many patients with chronic myelogenous leukemia, particularly in the chronic phase are asymptomatic so the lack of symptoms on physical examination cannot necessarily rule out the presence of chronic myelogenous leukemia.

Laboratory Evaluation

If your doctor suspects that you may leukemia, he/she will order a variety of blood tests including:

  • Complete blood count (CBC)

  • Differential and platelet count - this test is used to evaluate blast formation, thrombocytosis, thrombocytopenia, and basophilia.

  • Bone marrow aspiration and biopsy - a bone marrow sample is obtained from the hip bone or the breastbone and is examined under a microscope for appearance of abnormal cells and to measure the percentage of blasts and basophils in the bone marrow.

Cytogenetic Analysis

The term "cytogenetic analysis" refers to the examination of cells under a microscope to determine if there are any genetic (chromosomal) abnormalities. Cytogenetic analyis is performed to detect the presence of the Ph chromosome in marrow cells which is the "gold standard" for the diagnosis of chronic myelogenous leukemia.

In addition to cytogenetic analysis, other techniques may be used to detect the abnormal BCR-ABL fusion gene that is characteristic of chronic myelogenous leukemia. These techniques include the polymerase chain reaction (PCR) and fluorescence in situ hybridization (FISH).

Cytogenetic analysis, PCR, and FISH are also useful tools in monitoring the response of chronic myelogenous leukemia patients to therapy. A complete cytogenetic response to therapy would be indicated by the disappearance of the Ph chromosome in marrow cells after treatment. A positive molecular response to therapy would be indicated by the failure to detect the abnormal BCR-ABL fusion gene after treatment.