The problem with this model, according to Dr. Jessup, is that, while more than 150 hospitals in the U.S. currently perform the qRT-PCR assay for BCR-ABL, and it has proven quite sensitive for molecular monitoring of CML. “None of these hospital laboratories can directly compare their results to any other.” He proposes that daily use of a calibrator/control for the assay could “harmonize results between labs, but a control is not readily available now.”
Dr. Jessup said that, “each lab becomes a silo of efficiency,” and “reproducibility within labs is excellent”; however, studies have shown considerable differences in the copy number of BCR-ABL between laboratories in samples taken at the time of diagnosis and after treatment. “The CLIA process reinforces precision,” but not as much accuracy, added Dr. Jessup.
He described global harmonization efforts under way to standardize the multitude of home-brew qRT-PCR assays, including an International Standardization Project in Australia and efforts to develop reference standards for use across Europe. In the U.S., the NCI will facilitate development of standards and reagents for the BCR-ABL assay.