A self-calibrated, magnetic binding assay (e.g., sandwich, competitive, etc.) for detecting the presence or quantity of an analyte residing in a test sample is provided. The magnetic binding assay includes detection probes capable of generating a detection signal (e.g., fluorescent non-magnetic particles) and calibration probes capable of generating calibration signal (e.g., fluorescent magnetic particles). The amount of the analyte within the test sample is proportional to the intensity of the detection signal calibrated by the intensity of the calibration signal.