Arkray Drabkin's Solution with Standard is a reagent used for the quantitative, colorimetric determination of hemoglobin concentration in whole blood, utilizing the cyanmethemoglobin method. It contains potassium ferricyanide, potassium cyanide, and other components to convert hemoglobin to cyanmethemoglobin, which is then measured spectrophotometrically at 540 nm. The standard component allows for calibration and accurate measurement of hemoglobin levels.