1. A specimen analysis system to analyze specimen test articles which include at least one optical test subject substance marker that indicates at least a presence or an absence of a test subject substance in a specimen, and at least one optical specimen validity marker, a color of which indicates a validity of the specimen, the specimen analysis system comprising: at least one processor; and at least one non-transitory processor-readable medium that is communicatively coupled to the at least one processor and that stores at least one of processor-executable instructions or data that, when executed by the at least one processor, cause the at least one processor to: receive a set of image information that represents an image of at least a specimen validity portion of the specimen test article which includes the at least one optical specimen validity marker, the color of which indicates the validity of the specimen; determine a set of color component values for one or more of a plurality of pixels of the image that are representative of the specimen validity portion of the specimen test article, the set of color component values comprising at least three color component values, each of the color component values representative of an amount of a respective color component of a color of the corresponding one or more of the plurality of pixels of the image; and assess at least one specimen validity characteristic of the specimen based at least in part on each color component value of the determined set of color component values for the one or more of the plurality of pixels of the image.