A method of using a non-invasive analyte reading device to substantially continuously measure the presence, absence, or concentration of one or more analytes in a tissue of a subject includes wearing the non-invasive analyte reading device constantly or for at least the duration of the desired measurement period; and using the non-invasive analyte reading device to non-invasively measure the presence, absence, or concentration of one or more analytes in a tissue of a subject substantially continuously.