A flow cell including inlet and outlet ports in fluid communication with each other through a flow channel that extends therebetween. The flow channel includes a diffuser region and a field region that is located downstream from the diffuser region. The field region of the flow channel directs fluid along reaction sites where desired reactions occur. The fluid flows through the diffuser region in a first flow direction and through the field region in a second flow direction. The first and second flow directions being substantially perpendicular.