Molecular HematologyHematology

Translocation PML/RARa Quant. RT-PCR (MRD)

Normal Range
Not Detected
Sample Type
Whole Blood
Fasting
No
Unit
Ratio/Copy Number

Function

This is a highly sensitive molecular test using Quantitative Real-Time Polymerase Chain Reaction (RT-PCR) to detect the PML/RARa fusion transcript. This transcript results from a reciprocal translocation between chromosomes 15 and 17 [t(15;17)], which is the genetic hallmark of Acute Promyelocytic Leukemia (APL).

Why it is Ordered

This test is used for both initial diagnosis and long-term monitoring of APL patients. It is the gold standard for measuring Minimal Residual Disease (MRD).

  • Diagnosis: To confirm the specific subtype of leukemia and initiate targeted therapy (like ATRA and Arsenic Trioxide).
  • Monitoring: To see how well treatment is working.
  • Early Relapse Detection: To identify a molecular relapse (reappearance of the transcript) before a clinical relapse (reappearance of cancer cells in blood) occurs, allowing for early intervention.

Associated Conditions

  • Acute Promyelocytic Leukemia (APL): A specific, once-deadly but now highly curable form of AML.
  • Molecular Remission: When the RT-PCR can no longer detect the fusion transcript in the blood or bone marrow.

Why Context Matters

RT-PCR is extremely sensitive and prone to laboratory contamination if strict protocols aren't followed. Furthermore, the source of the sample (Bone Marrow vs. Peripheral Blood) can affect the sensitivity; bone marrow is generally more sensitive for detecting low-level residual disease. Variations in laboratory 'LOQ' (Limit of Quantitation) can also lead to different interpretations of 'low-positive' results.

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 Translocation PML/RARa Quant. RT-PCR (MRD):

Research & Guidelines

Related Indicators

JAK-2 Mutation (Exon 14, 12)

View Range
DR

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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