A method for measuring analyte concentration in a body fluid involves taking reflectance readings from a first surface of a porous reagent-containing matrix both before and after a sample of the fluid has been applied to a second surface of the matrix. A sequence of reflectance measurements is initiated...http://www.google.com/patents/US6268162?utm_source=gb-gplus-sharePatent US6268162 - Reflectance measurement of analyte concentration with automatic initiation of timing
