CML causes rapid growth of the blood-forming cells (myeloid precursors) in the bone marrow, blood, and body tissues.

Chronic myelogenous leukemia is grouped into several phases:

• Chronic
• Accelerated
• Blast crisis

The chronic phase can last for months or years. The disease may have few or no symptoms during this time. Most people are diagnosed during this stage, when they are having blood drawn for other reasons.

The accelerated phase is a more dangerous phase, during which the leukemia cells grow more quickly. This phase may be associated with fever (without infection), bone pain, and a swollen spleen.

If untreated, CML progresses to the blast crisis phase. Bleeding and infection may occur due to bone marrow failure. Other possible symptoms include:

• Bleeding and bruising
• Excessive sweating (night sweats)
• Fatigue
• Low-grade fever
• Pressure under the left ribs from a swollen spleen
• Sudden appearance of small red marks on the skin (petechiae)
• Weakness

A physical examination often reveals a swollen spleen. A complete blood count (CBC) shows an increased number of white blood cells.

Other tests that may be done include:

• Bone marrow aspiration and biopsy
• CBC with white blood cell differential
• Testing for the presence of the Philadelphia chromosome

This disease may also alter the results of the following tests:

• Platelet count
• Uric acid
• Vitamin B12 level