The Beckman Coulter Clinic team was asked to provide a means for distinguishing superparamagnetically labeled micrometer-sized spheres as they travel through a flow cytometer. By adding a new parameter, such as magnetism, the company would increase the number of analytical reactions that can be carried out simultaneously and detected in bead-based multiplexing. The team has investigated several methods of detection, simulated the best method and conducted proof-of-concept experimentation.