Fluid collection devices, analysis instruments and methods for making and using same are disclosed. The fluid collection device is provided with a device and an electrochemical cell. The device has first and second walls defining a microfluidic channel, and a sample application port communicating with the microfluidic channel. The first wall and the second wall are spaced a distance less than 150 microns. The electrochemical cell is disposed on the first wall to contact a sample travelling through the microfluidic channel. The electrochemical cell comprising molecule receptors such that a physical property of the first electrochemical cell is effected upon one or more of the molecule receptors binding to an electroactive species within the sample.