An international study to standardize the detection and quantitation of BCR-ABL transcripts from stabilized peripheral blood preparations by quantitative RT-PCR

Due to the lack of comparability of BCR-ABL mRNA quantification results generated by various methodologies in different laboratories, an international multicenter trial was started with the participation of six laboratories (platforms: LightCycler™, LC, n=3; TaqMan™, TM, n=3). One hundred and eighty-six PB samples derived from healthy donors were spiked with serial dilutions (1:20 to 1:2×10⁶) of b2a2, b3a2 or e1a2 BCR-ABL positive white blood cells (WBC) from leukemic patients. After PAXgene™ stabilization, blinding, freezing and distribution, standardized RNA extraction, cDNA synthesis, PCR protocols and data evaluation were carried out. There was no significant difference in the results achieved using LC and TM technologies, but a considerable overall variation (CV=0.74 for ratios BCR-ABL/ABL). Up to a dilution of 1:1,000, 27/30 of the 2.5 mL samples tested positive. For higher dilutions, a PB volume of 5 or 10 ml was required to improve sensitivity. The study showed the feasibility of RQ-PCR standardization independent of the PCR machine used.