I am trying to make a circuit to implement a Galvanic skin response sensor to measure the skin resistance and then use it to find the skin conductance. Then, I wish to calibrate these readings with some standard data so that the actual body hydration level can be calculated. In order to do so, I used one of the reference designs of Texas Instruments (Link). (The discussion related to this project is running on another TI forum with the link HERE.) The final circuit has been pasted below. The circuit has been implemented using hardware and I am getting voltage values from the op amp output terminal. The problem arises when I cannot compare these values with some standard data that is used in the Clinical labs for measuring body hydration level. So, the voltage values that I get cannot help in finding whether the person's body hydration level is high/low/some xyz value.
I need to calibrate these readings with some standard data so that the actual body hydration level can be calculated. Where can I get the standard data that I use for the calibration? OR is there some alternative approach to calibrate my readings? Thanks in advance.