Diagnosing Chronic Myelogenous Leukemia (CML) typically involves a combination of physical exams, blood tests, bone marrow tests, and specific tests to identify the Philadelphia chromosome. Here’s a breakdown:
Steps in Diagnosing CML
1. Physical Exam
Your healthcare provider will perform a physical exam, checking vital signs like pulse and blood pressure, and looking for any physical signs or symptoms that may indicate CML, such as an enlarged spleen.
2. Blood Tests
Blood tests are crucial in diagnosing CML. These tests can include:
- Complete Blood Count (CBC): This measures the number of different types of blood cells in your sample. In CML, the CBC often shows an elevated white blood cell count, especially neutrophils.
- Blood Smear: A sample of your blood is examined under a microscope to look for abnormal cells, including immature white blood cells (blasts).
3. Bone Marrow Tests
Bone marrow tests are essential for confirming the diagnosis of CML. These tests involve:
- Bone Marrow Aspiration: A needle is used to withdraw a liquid sample of bone marrow.
- Bone Marrow Biopsy: A needle is used to remove a small piece of bone and bone marrow.
These samples are then examined under a microscope to:
- Evaluate the number and maturity of blood cells.
- Look for the presence of abnormal cells.
- Assess the percentage of cells with the Philadelphia chromosome (see below).
4. Tests for the Philadelphia Chromosome
These tests are crucial in confirming the presence of the Philadelphia chromosome, a hallmark of CML. Two common tests include:
-
Cytogenetic Analysis: This test analyzes the chromosomes in the bone marrow cells to look for the Philadelphia chromosome. It directly visualizes the chromosomal translocation.
-
Fluorescence In Situ Hybridization (FISH): This test uses fluorescent probes to detect the BCR-ABL1 gene fusion, which is created by the Philadelphia chromosome. FISH is more sensitive than cytogenetic analysis.
-
Polymerase Chain Reaction (PCR): PCR is a highly sensitive test that can detect even small amounts of the BCR-ABL1 gene. PCR is often used to monitor the response to treatment in CML patients.
Summary
The diagnosis of CML requires a multi-faceted approach involving physical examination, blood tests, bone marrow tests, and tests to identify the Philadelphia chromosome. These tests help confirm the diagnosis, assess the extent of the disease, and guide treatment decisions.
