Abstract: An apparatus for isolating rare cells from a blood sample is disclosed. The apparatus includes a reservoir for supplying the blood sample and a pump for receiving the blood sample. The apparatus also includes a microchip and a set of magnets. The microchip has a microchannel formed between the microchip and a glass slide. The microchannel is connected between the reservoir and the pump to allow the blood sample to flow from the reservoir to the pump. The set of magnets is located adjacent to the glass slide to form a magnetic gradient along the glass slide on which rare cells can be isolated from the blood sample.