A field portable diagnostic apparatus uses a rotatable disk in which a microfluidic circuit is defined. The microfluidic circuit includes a centrifugal separation chamber receiving a sample to stratify the sample. A magnetic bead holding chamber is communicated to a mixing chamber, where mass amplifying functionalized magnetic-nanoparticles, held in a buffer solution and contained in the magnetic bead holding reservoir communicated to mixing chamber, are mixed with the separated fluid delivered to mixing chamber from the separation chamber. The functionalized magnetic nanoparticles conjugate with a target analyte in the sample. A magnet in proximity to a SAW chamber including a SAW detector draws the functionalized magnetic nanoparticles toward antibodies immobilized on the SAW sensor surface A wash reservoir is communicated to the SAW sensor chamber, and a cleanup/waste reservoir is communicated to the SAW chamber for receive fluid after it has passed through the SAW chamber.