Abstract: This invention is a method for determining a hematocrit value. The steps include applying a first pulse of potential excitation at a first frequency to a test strip containing a fluid sample. The method also includes applying a second pulse at a second frequency that is higher than the first frequency. Based on first and second impedance measurements associated with each pulse, a hematocrit value may be determined. Also, a concentration of an analyte contained within the fluid sample may be determined based on the hematocrit value.

Abstract: A system and method for detecting substances such as glucose in tissue. The system comprises an assay device and an optical apparatus. The assay device comprises a reactive region that is responsive to at least one substance in fluid to be collected from the tissue when the fluid is in contact with the reactive region, and which reactive region is also responsive to a first type of optical energy suitable to heat up and transfer heat by conduction to the tissue to ablate the tissue and form at least one opening in the tissue from which fluid is collected. The optical apparatus has an activation head to which the assay device is attached, and a first optical energy source that outputs a first type of optical energy. An optical detecting device is included in the optical apparatus that measures a characteristic of the at least one substance from the response of the reactive region when the reactive region is in contact with the at least one substance.