Methods for detecting analytes in a sample are provided. A plurality of
particles, each of which is coated with a capture agent having an
affinity for the analyte, is combined with the sample to form a plurality
of analyte-particle complexes. The system also includes a transport
arrangement for transporting the sample to the sensor surface, and a
magnetic field inducing structure constructed and arranged to establish a
magnetic field at and adjacent to the sensor surface. The resonant sensor
produces a signal corresponding to an amount of analyte-particle
complexes that are bound to the sensor surface.