A sensor is provided for the detection of a marker in a sample in which the sensor includes a high frequency 500 kHz-1 GHz piezoelectric ceramic resonator, with the system measuring resonant frequency change. In one embodiment, the piezoelectric sensor operates in the thickness extensional (TE) mode, with the high frequency and TE mode permitting fabrication of an exceptionally small size sensor capable of being arrayed in a handheld unit.