An electrochemical test sensor for detecting the concentration of an analyte in a fluid sample. An order management system may include a virtual shopping cart interface that may be used with a number of merchants. Sub-carrier frequencies and frequency-band characteristics may be selected with respect to channel characteristics. Moreover, the antenna feed line can be easily fixed inside the portable terminal. After cleaning the workpiece, the sponge may be exposed to a sponge cleaning fluid, which may or may not alter the surface charge of the sponge.