The present invention relates to methods for the extraction of nucleic acids from cells, the amplification of segments of nucleic acid and the detection of nucleic acids, all in a convenient and portable manner. In one embodiment, a sample comprising cells containing nucleic acid is exposed to an aqueous mixture comprising a lytic reagent and one or more beads capable of binding the nucleic acid released from said cells to form a nucleic acid-bead complex. The nucleic acid-bead complex is passed through an immiscible liquid layer to separate the nucleic acid from the aqueous mixture. The one or more beads are magnetic, and the nucleic acid-bead complex is passed through and separated from the immiscible liquid layer with an applied magnetic field. The invention is particularly suited for use in point-of-care medical diagnostics testing.