BCR-ABL Test: Purpose and Procedure Explained

Some cancers leave behind a clear genetic fingerprint. In chronic myelogenous leukaemia (CML) and certain types of acute lymphoblastic leukaemia (ALL), that fingerprint is the BCR-ABL1 gene—a fusion of two normally separate genes found on an abnormal chromosome 22, known as the Philadelphia chromosome.

Unlike most cancers, these forms of leukaemia can be traced to a single, defined mutation. The BCR-ABL test is designed to detect this specific abnormality. The BCR-ABL test full form is Breakpoint Cluster Region–Abelson Murine Leukaemia Viral Oncogene Homolog 1 test.

In this post, we will learn what the BCR-ABL quantitative test reveals, why it matters for diagnosis and treatment, and how the procedure is done.

What is the BCR-ABL Test?

The BCR-ABL test is a genetic test that checks for an abnormal gene called BCR-ABL1, commonly present in people with chronic myeloid leukaemia (CML). The gene is also found in acute lymphoblastic leukaemia (ALL) or acute myeloid leukaemia (AML), though less frequently. This gene is not inherited. It is acquired due to a mutation where parts of chromosomes 9 and 22 fuse, forming the Philadelphia chromosome.

The abnormal gene produces a faulty protein that causes the bone marrow to create excess abnormal white blood cells, leading to leukaemia. The test uses a blood or bone marrow sample to detect the BCR-ABL1 gene, its protein product, or the presence of the Philadelphia chromosome.

There are different versions of the test, including RT-PCR methods. Since it's an acquired mutation, it doesn't pass from parents to children.

Purpose of the BCR-ABL Test

The BCR-ABL test is essential for diagnosing and managing certain blood cancers, especially chronic myeloid leukaemia (CML) and Philadelphia chromosome-positive acute lymphoblastic leukaemia (Ph+ ALL). These cancers are linked to the BCR-ABL1 gene.

Your doctor may recommend the BCR-ABL quantitative test if you show symptoms such as unexplained fatigue, fever, weight loss, night sweats, high white blood cell count, or swollen lymph nodes.

The purpose of the test is to,

• Confirm a diagnosis of CML or Ph+ ALL.
• Guide treatment using targeted therapies that act on the BCR-ABL1 protein.
• Monitor treatment progress by checking if BCR-ABL1 levels are decreasing.
• Detect relapse after treatment completion.

BCR-ABL Test Procedure

The BCR-ABL test procedure may involve a blood sample or, in some cases, a bone marrow sample, depending on your condition and doctor’s recommendation.

Sample Collection

Blood Test: A healthcare professional draws a small amount of blood from a vein in your arm using a thin needle. The process takes about five minutes. You might feel a slight sting when the needle is inserted or removed. The sample is sent to a lab for genetic analysis, and results are available in a few days.

Bone Marrow Test: In certain cases, a bone marrow sample may be required for more detailed testing. It is usually done from the back of the hip bone. The procedure includes two parts:

• Aspiration: A thin needle is used to draw bone marrow fluid.
• Biopsy: A hollow needle is inserted and twisted to remove a small piece of bone marrow tissue.

You’ll receive a local anaesthetic and possibly a sedative. The procedure lasts only a few minutes and the site will be bandaged afterwards. You’ll lie down for about 15 minutes to ensure bleeding stops.

Preparation

For a standard blood test, no special preparation is required. However, for a bone marrow test, your healthcare provider may advise you to fast for a few hours before the procedure. You should also inform your provider about any medications you're taking and provide a complete medical history.

Risks and Recovery

Blood Test Risks: The risks of the blood test are minimal. There may be slight bruising or discomfort at the puncture site. For adults, it won’t be a problem.

Bone Marrow Test Risks: You may feel soreness or stiffness at the site for a few days. If needed, your doctor can discuss pain relief.

BCR-ABL Test Results

BCR-ABL test results are important to monitor the related health conditions. The BCR-ABL test normal range is 0–0.1%. A result above the normal range may indicate the presence of CML or a related disorder.

After treatment begins, three interpretations are possible:

• Increasing BCR-ABL levels suggest the therapy is ineffective.
• Decreasing levels indicate a positive response.
• Stable levels may mean disease control, but warrant further monitoring.

Doctors assess these results alongside other findings, e.g. abnormal white blood cell counts and the Philadelphia chromosome. Testing is usually done at diagnosis and repeated periodically to check for remission, resistance or relapse.

BCR-ABL changes are reported as minor, partial, major, or complete response, depending on the treatment effectiveness.

Different laboratories may use varying methods to detect the BCR-ABL1 gene and the Philadelphia chromosome, which can influence the results. For consistent and accurate monitoring, it’s best to perform your tests using the same method and at the same lab. Your healthcare provider can also reliably compare results over time.

BCR ABL Test Price

In India, the BCR-ABL test price ranges from ₹4,000 to ₹8,000, depending on the city, testing method (qualitative or quantitative) and laboratory infrastructure. Advanced versions like quantitative PCR on the international scale may cost more, even exceeding ₹10,000 in some locations. Most providers offer home sample collection and online booking options as well.

Tracking BCR-ABL Levels: What Frequency Is Recommended?

One important aspect of BCR-ABL testing is how frequently it should be done. Regular monitoring is recommended for patients undergoing treatment for CML or Ph+ ALL. It can gauge the effectiveness of therapy and detect early signs of resistance or relapse.

Stage	Recommended Testing Frequency	Purpose
At Diagnosis	Once	Establish baseline BCR-ABL level
During Initial Treatment	Every 3 months	Monitor response and detect early treatment failure
After Achieving MMR	Every 3 to 6 months	Ensure continued molecular response
Post-Treatment / In Remission	Every 6 to 12 months (or as advised)	Detect signs of relapse or residual disease
If Treatment Is Changed or Resumed	Immediately after the change, then every 3 months	Assess response to new therapy

Skipping or delaying these tests may risk missing subtle changes in disease activity. Following a structured testing schedule ensures timely therapeutic adjustments and improves long-term outcomes.

Conclusion

The BCR-ABL test is a powerful diagnostic and monitoring tool in managing CML and related blood cancers. Its high sensitivity allows it to detect even minimal amounts of the BCR-ABL gene. Staying consistent with testing frequency and following medical advice promises the best possible outcomes throughout care.

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