The Xpert BCR-ABL 0% IS is designed to be used as an external quality control assayed to monitor the performance of quantitative in vitro detection of BCR-ABL1 e14a2 / b3a2 translocation mRNA transcripts and control mRNA transcription. endogenous ABL1 when analyzed with Xpert® BCR-ABL Ultra Assay on Cepheid GeneXpert® instrument systems.
The Philadelphia chromosome, a translocation between the ABL1 gene on chromosome 9 and the BCR gene on chromosome 22, designated t (9; 22), generates the BCR-ABL1 fusion gene that is present in most patients with chronic myelogenous leukemia.
Quantitative monitoring of BCR-ABL1 transcripts in the patient’s blood is an important tool for measuring response to therapy. In 2009, the World Health.
Organization (WHO) developed a panel of four BCR-ABL1 primary standards to establish an International Scale (IS), a standardized method for reporting test results as a ratio of fusion transcripts to transcripts of control genes (% IS), useful for the harmonization of patient care in laboratories around the world1,2. % IS can also be expressed as molecular response (MR), the log reduction from a standardized baseline of 100% in the IS.
The Xpert BCR-ABL IS Panel C130 is traceable to the WHO International Genetic Reference Panel for the quantification of BCR-ABL translocation (WHO Reference Panel), NIBSC code 09/138, and is designed to its use with the internationally reported Xpert BCR-ABL Ultra Assay.
PRODUCT SUMMARY and PRINCIPLE:
Xpert BCR-ABL 0% IS is composed of one tier, Xpert BCR-ABL 0% IS, which contains synthetic RNA transcripts of the ABL1 control gene. This control is designed to represent a sample without the BCR-ABL1 fusion gene present when analyzed on the GeneXpert System with the Xpert BCR-ABL Ultra Assay. Xpert BCR-ABL 0% IS is a component of the Xpert BCR-ABL IS Panel C130, part number C130.
Validation and value assignment
MMQCI manufactured 3 lots of Xpert BCR-ABL IS Panel C130 and tested them together with the WHO Reference Panel, using one lot of Xpert BCR-ABL Ultra Assay cartridge. Grubb outliers and Bland-Altman tests were applied, lot-specific correction factors (CFs) were calculated, and WHO-traceable% IS / MR values were assigned to each level of the Xpert BCR-ABL IS Panel.
C130 for the 3 lots according to NIBSC 3 Instructions for Use. Figure 1. compares the 3 lots of Xpert BCR-ABL IS Panel C130 with the 4 members of the WHO Reference Panel. New lots of Xpert BCR-ABL IS Panel C130 will be assigned lot-specific% IS / MR values in the same way.
Figure 1. Three lots of Xpert BCR-ABL IS Panel C130 calibrated according to the WHO International Genetic Reference Panel for the quantification of BCR-ABL translocation.