Objective: To revalidate the conversion factor（CF）for the conversion of BCR-ABL （P210）transcript levels to the international scale（BCR- ABLIS）in chronic myeloid leukemia（CML） which validated before.
Methods: Peking University People's Hospital（PKUPH）prepared the exchange samples for revalidation of CFs of 15 laboratories which validated nine or eighteen months ago. The fresh BCR-ABL（P210）（+）bone morrow or peripheral blood nucleated cells were diluted with BCR-ABL （P210）（-）cells to achieve different BCR- ABL levels, totally 16 sets and 24 samples per set were prepared. TRIzol reagent was added in each tube. Each laboratory tested BCR-ABL transcript levels of one set of samples. Agreement between BCR-ABLIS of each laboratory and PKUPH was assessed by the Bland- Altman method. For laboratories which did not meet the criteria of revalidation, linear regression equation was derived after the samples with maximum BCR-ABL deviation were removed until R²>0.98, then new CF was calculated.
Results: 10 laboratories met the revalidation criteria with both bias within ±1.4 fold and 95% limits of agreement within ±6 folds, and their CFs still could be used for accurately conversion of BCR-ABLIS. New CFs were recalculated as of 1.8-6.3 folds of their previous CFs in 5 laboratories not met the criteria.
Conclusion: Revalidation of CF by sample exchange among laboratories was necessary for accurate and continuous application of BCR-ABLIS, which not only tested the validity of CF acquired before but also calculated new available CFs for those with invalid CFs.
目的: 再确认已获得的用于转换慢性髓性白血病国际标准化的BCR-ABL (P210)转录本水平(BCR-ABLIS)的转换系数(CF)的有效性。
方法: 北京大学人民医院(简称PKUPH)统一制备用于再确认15家单位9或18个月之前已获得的CF的比对样品，即用BCR-ABL阴性患者骨髓或外周血有核细胞稀释BCR-ABL(P210)阳性细胞制备出相同16套、每套24种不同BCR-ABL水平的样本，加入TRIzol中。15家单位分别检测1套，采用GraphPad Prism 5.0软件对其与PKUPH的BCR-ABLIS检测值分别进行Bland-Altman一致性分析。对于未达到再确认标准的单位，去除结果明显偏离的样本直至其检测值与PKUPH的BCR-ABLIS之间的回归方程相关系数>0.98，来计算新的CF。
结果: 10家单位达到标准(偏倚介于±1.4倍，且95％可信区间介于±6.0倍)，说明原有的CF依然准确，可以继续有效转换BCR-ABLIS。5家未达到标准的单位通过重新计算得出新的CF，分别是原有CF的1.8~6.3倍。
结论: 通过室间样本比对的CF再确认过程既检验了原有CF是否依然有效，又使CF不再有效的单位获得新的适用于当前的CF，保持了BCR-ABLIS应用的准确性和连续性。