An improved method for the calibration of continuously recorded dye dilution curves.

ONE of the main problems in the use of continuously recorded dye dilution curves has been the calibration of the obtained curves. Methods involving measurements from the "tail" of the dilution curve are often inaccurate because in this portion of the curve the concentration of dye is low. Other methods of calibration involve determinations from a sample of blood withdrawn before or after the dilution curve has been recorded. A method of calibration has been developed which avoids many of these difficulties. I t involves the use of a sample of the same blood which is being withdrawn through the cuvette for the inscription of the dye curve and is therefore of a much higher concentration. The calibration is carried out by determining the mean concentration of dye in the sample and determining the mean deflection over the period of the collection.