Methods and systems for measuring and using the oxidation-reductioncharacteristics of a biological sample are provided. The system generallyincludes a teststrip and a readout device. A fluid sample is placed in the test strip, andthe test strip is inturn operatively connected to the readout device. The readout device providesa controlledcurrent that is sent across the fluid in the sample chamber. In addition, thereadout deviceidentifies an inflection point or transition time at which the voltage betweencontacts ofthe test strip is changing at the highest rate. The oxidation-reductioncapacity of thesample is taken as the integral of the current profile from the time at whichcurrent beginsto be supplied to the sample to the identified transition time.
