Analytical performance evaluation and method comparison of the 1copy BCR::ABL1 qPCR assay for monitoring chronic myeloid leukemia

Accurate BCR::ABL1 quantification is essential for monitoring chronic myeloid leukemia (CML), particularly at the major molecular response (MMR; ≤0.1% IS) and deep molecular response (DMR) levels: MR4 (≤0.01% IS) and MR4.5 (≤0.0032% IS). We evaluated the analytical performance of the 1copy BCR::ABL1 qPCR Kit (1drop, Republic of Korea), a one-step real-time quantitative PCR (qPCR) Kit and compared it with two established assays.

Precision, linearity, and detection capability (LoB, LoD, LoQ] were assessed according to Clinical and Laboratory Standards Institute (CLSI) guidelines. A method comparison study was performed using 74 clinical samples tested concurrently with the ipsogen BCR::ABL1 Mbcr IS-MMR Kit (Qiagen, Hilden, Germany) and the QXDx BCR::ABL %IS droplet digital PCR (ddPCR) assay (Bio-Rad, Hercules, CA, USA). Concordance was further evaluated at clinically critical molecular response thresholds (>10%, >1%, and ≤0.1% international scale [IS]).

The coefficients of variation at 14.1% IS and 0.233% IS were 14.4% and 15.6%, respectively. The assay was linear across a 5-log range (0.02-85% IS; R² = 0.9949). The manufacturer-claimed LoB, LoD, and LoQ were verified. Pearson correlation coefficients with the ipsogen and QXDx assays were 0.951 and 0.950, respectively. Concordance at the >10% IS, >1% IS, and ≤0.1% IS thresholds was 98.6%, 100%, and 95.9% (vs. ipsogen), and 100%, 100%, and 90.5% (vs. QXDx), respectively.

The 1copy BCR::ABL1 qPCR assay demonstrated reliable analytical performance and high concordance with established quantitative assays at clinically relevant molecular response thresholds, supporting its utility for routine monitoring of CML.