An improved oximeter device for the calculation of oxygen saturation in arterial blood is provided. A pair of LED's are positioned to transmit red and infrared light through tissue containing the blood. A photo electric converter is provided to receive the transmitted light and convert it into a electrical signals. The probe can store data directed to various characteristics of the LED's, such as the primary wavelength and a secondary wavelength of the LED and an indication of the amount of crosstalk that can occur in the signals. The correction of any errors resulting from crosstalk plus the calculation of oxygen saturation depending on the various characteristics of the LED's can be effectuated.