[A multicenter study on the revalidation of validated conversion factor for the conversion of BCRABL（P210）transcript
Yazhen Qin1, Daoxin Ma, Yungui Wang
1Peking University People's Hospital, Peking University Institute of Hematology, Beijing 100044, China.
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.
