CPT® Code 81316

PML/RARalpha, (t(15;17)), (promyelocytic leukemia/retinoic acid receptor alpha) (eg, promyelocytic leukemia) translocation analysis; single breakpoint (eg, intron 3, intron 6 or exon 6), qualitative or quantitative

The CPT® Code 81316 pertains to the molecular genetic testing specifically designed to analyze the PML/RARalpha translocation, which is a critical genetic alteration associated with promyelocytic leukemia. This test focuses on identifying a single breakpoint within the translocation between the PML gene located on chromosome 15 and the RARalpha gene on chromosome 17. The presence of this translocation is a hallmark of acute promyelocytic leukemia (APL), a subtype of acute myeloid leukemia (AML). In approximately 99% of APL cases, this genetic rearrangement results in the formation of a chimeric fusion gene, which can lead to the production of different isoforms based on the specific breakpoint location. The analysis can be performed qualitatively or quantitatively, allowing for the detection of the fusion transcripts that indicate the presence of the translocation. The test can utilize techniques such as reverse transcription-polymerase chain reaction (RT-PCR) to amplify the RNA extracted from the patient's sample, enabling the identification of either long or short isoforms of the PML/RARalpha fusion gene. The results of this testing are crucial for diagnosing APL, monitoring treatment effectiveness, assessing minimal residual disease (MRD), and predicting potential relapse. The identification of specific breakpoints, such as those found in intron 3, intron 6, or exon 6 of the PML gene, is essential for understanding the genetic landscape of the disease and tailoring appropriate therapeutic strategies.