Analytical Performance Evaluation of a Digital Real‐Time PCR for Quantifying Major BCR::ABL1 Transcripts

ABSTRACT Background Accurate quantification of the BCR::ABL1 transcripts is essential for measurable residual disease (MRD) monitoring in chronic myeloid leukemia (CML) after tyrosine kinase inhibitor (TKI) treatment. This study evaluated the newly developed digital real‐time PCR method, Dr. PCR, as an alternative reverse transcription‐PCR (qRT‐PCR) for MRD detection. Methods The performance of Dr. PCR was assessed using reference and clinical materials. Precision, linearity, and correlation with qRT‐PCR were evaluated. MRD levels detected by Dr. PCR were compared with qRT‐PCR, and practical advantages were investigated. Results Dr. PCR detected MRD up to 0.0032%IS (MR4.5) with excellent precision and linearity and showed a strong correlation with qRT‐PCR results. Notably, Dr. PCR identified higher levels of MRD in 12.7% (29/229) of patients than qRT‐PCR, including six cases of MR4, which is a critical level for TKI discontinuation. Dr. PCR also allowed for sufficient ABL1 copies in all cases, while qRT‐PCR necessitated multiple repeat tests in 3.5% (8/229) of cases. Conclusion Our study provides a body of evidence supporting the clinical application of Dr. PCR as a rapid and efficient method for assessing MRD in patients with CML under the current treatment regimen. A single cartridge is used per sample, housing around 20,000 microwells, each performing independent polymerase chain reactions (PCR). This enables precise quantification of the target gene at the single‐unit level, even when its concentration is very low. Quantification is confirmed by analyzing amplification curves and scatter charts generated during the PCR.