A machine readable assaying system including an assay card having a machine readable assaying indicia located upon a surface of the card. At least one analysis element is provided with the assaying indicia, and is capable of monitoring a parameter to detect and optically signal the presence or absence of a desired state. The analysis elements composing, at least in part, an assaying mechanism in the form a pattern of elements, generally additionally including at least one fixed element, and or at least one blank region.