Clinical-grade monitoring technology is disclosed for a number of applications where low-cost, wireless, multi-parameter, single-use and multi-use medical and fitness and/or wellness devices are useful and beneficial. A monitoring device that attaches or is placed on a measurement site includes at least one of an optical sensor, a temperature sensor, or first and second electrical contact sensors. Signals received from the optical sensor, a temperature sensor, and/or first and second electrical contact sensors can be transmitted to a host device. An application program on a host device can process the signals to compute one or more physiological parameters, waveform data, trend data, and/or one or more reports.
