BCR/ABL1 Gene Rearrangement, Quantitative, PCR

Casandra

Casandra Test Code QD12602Version 1 (DRAFT)

Performing Lab

Lab Quest DiagnosticsLab Test ID 91065CPT Codes 81206, 81207

BCR/ABL1 Gene Rearrangement, Quantitative, PCR

Also known as: P190 BCR-ABL transcript, MRDx BCR-ABL Test, t(9;22), Philadelphia Chromosome

Clinical Use

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Use

This test is used to detect and quantify the BCR‑ABL1 fusion transcript in patients with chronic myelogenous leukemia (CML) or acute lymphoblastic leukemia (ALL) that carry the t(9;22) Philadelphia chromosome. It detects both the P210 (e13a2 and e14a2) and P190 (e1a2) isoforms, and levels are expressed as the ratio of BCR‑ABL1 to ABL1 transcript, with P210 normalized to the international scale (IS) for monitoring molecular response.[turn0search0] It can detect a minimum of a 4.5‑log reduction (0.0032%) in transcript level relative to a universal baseline of 100%, with ≤0.1% corresponding to major molecular response (MMR).[turn0search0]

Special Instructions

If the BCR‑ABL1 fusion is detected on initial testing, subsequent testing will focus only on the previously detected isoform(s).[turn0search0]

Limitations

Approximately 1–3% of cases may harbor altered fusion transcripts (e.g., missing ABL1 exon A2) that the PCR assay cannot detect; FISH may be needed in these cases, such as for very rare P230 isoform or discordant PCR/FISH results.[turn0search0]

Test Details