BCR-ABL Translocation
- Sample Type
- Whole Blood
- Fasting
- No
- Unit
- % (IS)
Function
The BCR-ABL test is a highly specific molecular test that looks for a genetic abnormality known as the Philadelphia chromosome. This occurs when pieces of chromosomes 9 and 22 break off and switch places. This translocation creates a fusion gene, BCR-ABL, which produces a tyrosine kinase protein that causes white blood cells to grow uncontrollably. This test usually employs Quantitative Polymerase Chain Reaction (qPCR) to detect the number of fusion gene copies.
Why it is Ordered
This test is the definitive tool for diagnosing Chronic Myeloid Leukemia (CML) and a specific subtype of Acute Lymphoblastic Leukemia (Ph+ ALL). Beyond diagnosis, it is used to monitor the effectiveness of therapy with Tyrosine Kinase Inhibitors (TKIs). The goal of treatment is 'Molecular Response,' where the BCR-ABL levels become undetectable or extremely low.
Associated Conditions
- Chronic Myeloid Leukemia (CML): Over 95% of CML patients have this translocation.
- Acute Lymphoblastic Leukemia (ALL): Found in about 25% of adult ALL cases.
- Minimal Residual Disease (MRD): Used to check for remaining cancer cells after treatment.
Check Your Result
Check Your Result
Enter your lab result to see where you stand compared to the standard reference range.
Why Context Matters
The BCR-ABL test is extremely sensitive, and the quality of the sample is paramount. If the blood or bone marrow sample is not processed quickly, the RNA needed for the test can degrade, leading to a false-negative or an underestimation of the disease burden. Furthermore, different labs may use different scales; the 'International Scale' (IS) was created to standardize results, but discrepancies still occur. If a result shows a sudden 'loss of molecular response' (an increase in levels), a second opinion and a mutational analysis are often required to check if the leukemia has become resistant to the current medication.
Lab ranges are statistical averages, not biological laws. "Normal" for a 20-year-old male isn't normal for a 60-year-old female.
Clinical References
Source-of-truth databases and clinical guidelines for BCR-ABL Translocation:
Official Sources
- BCR-ABL1 Test - Testing.comTesting.com
- BCR gene: MedlinePlus GeneticsMedlinePlus
Research & Guidelines
- PubMed: BCR-ABL Translocation Clinical GuidelinesNCBI / PubMed
Related Indicators
Medically Reviewed by Dr. Binoy Babu, MBBS
Board Certified Doctor • 10+ Years Clinical Experience
Dr. Babu is a practicing physician dedicated to empowering patients with clear, actionable medical information. He founded 2opi to bridge the gap between complex lab reports and patient understanding, ensuring everyone has access to a reliable second opinion.
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