A system for detecting an analyte in a sample includes a resonant sensor that has a sensor surface coated with the capture agent. A plurality of magnetic 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.