Quantitative assessment of the BCR-ABL transcript using the Cepheid Xpert BCR-ABL Monitor assay

Area of Science:

• Molecular Biology
• Hematology
• Clinical Diagnostics

Background:

• Chronic myelogenous leukemia (CML) management relies on monitoring the BCR-ABL transcript.
• Tyrosine kinase inhibitors are standard CML treatments, necessitating routine transcript quantification.
• The Xpert BCR-ABL Monitor assay streamlines RNA isolation and quantitative RT-PCR in a single cartridge.

Purpose of the Study:

• To evaluate the Xpert BCR-ABL Monitor assay for quantitative assessment of the BCR-ABL transcript in CML patients.
• Assessing the assay's performance in detecting and quantifying BCR-ABL transcripts.

Main Methods:

• Sensitivity, linearity, and precision (percent coefficient of variation) were tested using a standard curve of K-562 cells.
• Specimen stability was assessed after 24 and 96 hours of refrigerated storage.
• Assay performance was evaluated on specimens from normal controls and CML patients.

Main Results:

• The assay detected 1 K-562 cell in 10(5) normal cells, indicating high sensitivity.
• A high linearity (R2 = 0.98) and acceptable precision (15%-24% CV) were observed.
• 11 of 14 CML patients on imatinib tested positive for BCR-ABL, while 10 normal controls tested negative.

Conclusions:

• The Xpert BCR-ABL Monitor assay is a rapid, sensitive, and reliable method for monitoring BCR-ABL transcripts in CML.
• Its single-use cartridge design reduces hands-on time and contamination risk.
• The assay enables quantitative BCR-ABL testing in a random-access format, improving CML patient management.