Description
Why It’s Done
This test is primarily used to:
• Diagnose acute promyelocytic leukemia (APL): The presence of the PML-RARα fusion gene confirms the diagnosis of APL, which has unique characteristics compared to other types of leukemia.
• Monitor treatment response: After initiating treatment for APL (usually with all-trans retinoic acid (ATRA) and chemotherapy), the RT-PCR test can be used to detect whether the PML-RARα gene is still present, indicating disease persistence or relapse.
• Assess minimal residual disease (MRD): RT-PCR is particularly valuable for detecting small amounts of leukemia cells (MRD) that remain after treatment and are difficult to identify with other tests, allowing for early detection of relapse.
• Confirm remission: A negative result after treatment suggests that the disease is in remission, but ongoing monitoring is often necessary.
The presence of the PML-RARα fusion gene is directly linked to the pathogenesis of APL, and its detection plays a critical role in confirming diagnosis and guiding therapy.
Preparation
• No fasting is required for this test.
• The test typically uses a blood or bone marrow sample:
o Blood sample: A blood sample is drawn from a vein in your arm.
o Bone marrow sample: In some cases, a bone marrow aspiration may be required, where a sample is taken from the hip bone.
• Timing: This test may be performed at multiple points in treatment to monitor disease progression or remission status.
• Medications: Inform your doctor about any medications or treatments you’re undergoing, as these can affect the results. For example, ATRA therapy, a standard treatment for APL, can influence gene expression during treatment monitoring.
