Method and apparatus for analyte detection having on-strip standard

An apparatus for determining the presence or quantity of an analyte in a sample applied to a portion of a longitudinally extending test strip;

• said portion having an optically visible surface defining a reaction zone which reaction zone varies in reflectance as a function of the quantity of analyte present in the applied liquid;
• said apparatus comprising:
• an opening for inserting the leading edge of said strip into said apparatus;
• a strip passageway extending from said opening and terminating at a strip impeding means for impeding the strip after it is fully inserted;
• an optical aperture through said passageway whereby a portion of the surface of the strip overlying said aperture is visible, said aperture positioned along said passageway so that when said strip is fully inserted said reaction zone of said strip is visible therethrough;
• optics, in optical communication with said optical aperture, said optics comprising at least one light source for directing light onto said portion of said strip and at least one reflectance detector for detecting light reflected from said portion of said strip;
• a microprocessor for controlling the optics as the strip is being inserted into the passageway and after the strip has reached the strip impeding means;
• said microprocessor being programmed to cause said light source and detector to make a plurality of readings of a standard zone provided on the surface of the strip leading the reaction zone and visible through the optical aperture as the strip is being inserted, and use the highest reading to provide a calibrated standard reflectance;
• said microprocessor being programmed to cause said light source and said detector to read the reflectance of the reaction zone after the strip has been inserted;
• and
• said microprocessor being programmed to determine the quantity of analyte in the sample as a function of said calibrated standard zone reflectance and the reflectance of the reaction zone;
• and
• means for reporting such quantity.