Quantification of BCR-ABL1 on the GeneXpert: From diagnostics to research

Abstract

The GeneXpert is an excellent point of care system which requires none to minimal processing of whole blood prior to analysis. However, this is also a potential disadvantage of the GeneXpert since its application in a research environment is limited especially for archived experimental and clinical trial samples that are often stabilized prior to medium to long term storage. Stabilization of white blood cells in TRIzol or its equivalent has been common practice to quantify BCR-ABL1 in patients with chronic myeloid leukemia, since it preserves nucleic acid integrity and allows for further analysis if required. We describe a novel method of using blood stabilized in TRI Reagent (an equivalent of TRIzol) on the GeneXpert for the quantification of BCR-ABL1. We investigated the use of white blood cells stabilized in TRI Reagent at six disease levels from BCR-ABL1 above 10% to BCR-ABL1 not detected with five patient samples in each group. We observed a 0.99 correlation in percentage BCR-ABL1 between fresh whole blood and white blood cells stored in TRI Reagent for up to 11months. A further advantage of this method is that it does not require RNA extraction prior to analysis on the GeneXpert. This approach extends the current capabilities of the GeneXpert to more than a typical point of care instrument by allowing retrospective analysis of archived samples.