Abstract: A method for detecting an analyte can include binding an analyte with a first reagent which is associated with a magnetic particle, allowing analyte to interact with an excess amount of a second reagent capable of interacting with the analyte, and magnetically separating a portion of analyte-bound second reagent from excess second reagent. After the magnetic separation, the interaction of the analyte and the second reagent can be disrupted to produce a detectable form of the second reagent, which can be detected. A device and system suited to performing the method are also described.