Patent ID: 8088578

Claim:
A method of detecting an analyte, the method comprising: (a) providing a droplet in a droplet operations gap of a droplet actuator in a detection window comprising an opening or window in a substrate of the droplet actuator, the droplet comprising: (i) a signal-producing substance indicative of the presence and/or quantity of an analyte; (ii) one or more magnetically responsive beads which may interfere with signal produced by the signal producing substance; (b) using a magnetic field for: (i) magnetically removing the magnetically responsive beads from the detection window, wherein the magnetic field aggregates the magnetically responsive beads in a region of the droplet which is outside the detection window; and/or (ii) magnetically restricting the magnetically responsive beads from entering the detection window while transporting and/or retaining the droplet in the detection window, wherein the magnetic field aggregates the magnetically responsive beads in a region of the droplet which is outside the detection window; (c) detecting a signal from the droplet within the detection window produced by the signal-producing substance to detect the presence, absence and/or quantity of the analyte while the magnetically responsive beads are outside the detection window.