BCR/ABL Quantification

Function

The BCR-ABL1 quantification test uses Real-Time Quantitative PCR (RQ-PCR) to measure the amount of the BCR-ABL1 fusion transcript in the blood or bone marrow. This transcript is the result of a genetic translocation known as the Philadelphia Chromosome (t(9;22)), which creates an abnormal tyrosine kinase protein that causes uncontrolled white blood cell growth.

Why it is Ordered

This is the 'gold standard' test for monitoring patients with Chronic Myeloid Leukemia (CML) and some types of Acute Lymphoblastic Leukemia (ALL). It is used for:

• Baseline Assessment: Quantifying the disease burden at diagnosis.
• Monitoring Therapy: Assessing the response to Tyrosine Kinase Inhibitors (TKIs) like Imatinib.
• Detecting Relapse: Identifying 'Molecular Relapse' long before physical symptoms or abnormal blood counts appear.
• Achieving MMR: Monitoring for Major Molecular Response (defined as BCR-ABL1 < 0.1% on the International Scale).

Associated Conditions

• Chronic Myeloid Leukemia (CML): The primary condition associated with this marker.
• Ph+ Acute Lymphoblastic Leukemia (ALL): A subset of ALL patients carry this mutation.
• Minimal Residual Disease (MRD): Assessing trace amounts of cancer cells during remission.