A novel tool for the detection of BCR/ABL fusion gene in chronic myelogenous leukemia (CML) was developed by a magneto-polymerase chain reaction (PCR)-enzyme linked gene technique. The forward primers covalently bound to the surface of magnetic nanoparticles allowed a convenient separation of PCR products with high sensitivity (0.5 pg ml(-1)) and high specificity using K562 cell line and CML patients. The results were obtained when the biotinylated-reverse primer bound to streptavidin-horseradish peroxidase (HRP) and hydrolysed the substrate. This novel readout system was approximately 1000-fold more sensitive than the conventional agarose gel electrophoresis. The present technique is practical and useful for following up CML patients and for providing appropriate treatment, particularly to patients in remote areas.