 Accurate and standardized methods for the quantitative measurement of BCR-ABL1 are a prerequisite for monitoring of treatment response in t(9;22)-positive leukemia.     ///    "Here, we describe a novel multiplex assay system based on the proven TaqMan and Armored RNA technologies and optimized for sensitive detection of three BCR-ABL1 fusion transcripts and ABL1 in a single reaction. "    ///    Direct comparison with a reference laboratory calibrated to the international scale (IS) demonstrated minimal analytical bias between methods and an overall accuracy and precision within the performance range required for quantitative measurement of BCR-ABL1 on the IS.     ///    Establishment of a standardized multiplex assay with the analytical performance required for quantitative measurement of BCR-ABL1 on the international reporting scale.. 