AffiCHECK® BCR-ABL 0%IS
The AffiCHECK® BCR-ABL 0%IS stands as a meticulously crafted tool, meticulously engineered as an assayed external quality control. Its primary role is to rigorously oversee and validate the in vitro quantitative detection of BCR-ABL1 translocation mRNA e14a2/b3a2 transcripts alongside the ABL1 endogenous control mRNA transcript. This examination occurs within the precision realm of the Xpert® BCR-ABL Ultra assay, an unparalleled system nestled within the Cepheid GeneXpert® Instrument Systems.
The genesis of its purpose finds its roots intertwined with the Philadelphia chromosome—a genetic symphony orchestrated by the translocation between chromosome 9's ABL1 gene and chromosome 22's BCR gene, designated as t(9;22). This genetic ballet gives rise to the enigmatic fusion gene, BCR-ABL1, a signature found in the majority of chronic myelogenous leukemia (CML) patients. The vigilant monitoring of BCR-ABL1 transcripts circulating within patient blood emerges as a pivotal instrument in deciphering and measuring the effectiveness of therapeutic interventions.
In a landmark stride toward global standardization, the year 2009 marked the genesis of the World Health Organization's (WHO) quest. Through the development of four primary BCR-ABL1 standards, the international scale (IS) was born—a beacon illuminating a standardized avenue to articulate assay outcomes as a ratio of fusion transcripts to control gene transcripts (%IS). This numerical realm transcends into a linguistic repertoire, expressed as molecular response (MR), depicting the logarithmic reduction from an esteemed 100% baseline.
A legacy tied to the WHO International Genetic Reference Panel for Quantitation of BCR-ABL Translocation (WHO Reference Panel), stamped with the prestigious NIBSC code 09/138, bequeaths the lineage of the AffiCHECK® BCR-ABL IS Panel. Crafted specifically to synergize with the Xpert BCR-ABL Ultra assay, this panel orchestrates an articulate narrative on the international scale—an ode to precision, reliability, and the orchestration of uniform patient care across laboratories spanning the globe.
The AffiCHECK® BCR-ABL 0%IS contains a single level, termed BCR-ABL 0%IS, housing synthetic RNA transcripts of the ABL1 control gene. This particular control level is meticulously designed to emulate a sample devoid of the BCR-ABL1 fusion gene when scrutinized using the Xpert BCR-ABL Ultra assay on the GeneXpert system. It serves as an integral component within the AffiCHECK® BCR-ABL IS Panel, identified by its part number, AFG-CHK-1000.
Regarding Validation and Value Assignment, AffiGEN manufactured three batches of the AffiCHECK® BCR-ABL IS Panel and subjected them to evaluation alongside the WHO Reference Panel. This evaluation involved the utilization of a single cartridge lot of the Xpert BCR-ABL Ultra assay. Various statistical analyses, including Grubb’s outlier and Bland-Altman tests, were employed. Unique Correction Factors (CF) were calculated for each lot, and subsequently, WHO-traceable %IS/MR values were assigned to every level within these three lots of the AffiCHECK® BCR-ABL IS Panel, adhering to the guidelines provided by NIBSC for Use. Figure 1 depicts a comparative analysis between the three lots of the AffiCHECK® BCR-ABL IS Panel and the four constituents of the WHO Reference Panel. Future batches of the AffiCHECK® BCR-ABL IS Panel will undergo a similar process to ascertain lot-specific %IS/MR values.
The AffiCHECK® BCR-ABL 0%IS package comprises five vials. Within these vials resides the crafted essence of synthetic ABL1 control gene transcript, delicately suspended within a stabilizing matrix, meticulously blended with a non-infectious solution housing buffers and preservatives.
AffiCHECK® BCR-ABL 0%IS Panel must be sored at -20°C. Unopened package remains stable until the indicated expiration date.