Patent ID: 6544793
Filing Date: 2003-04-08
Classification: G01N,Y10T

Abstract:
A method for calibrating a blood analyzer held within an optical scanning instrument, in order to determine the hematocrit (HCT) value of a sample of blood, said method comprising:a) providing a chamber for receiving a blood sample, in said blood analyzer; b) depositing the sample into said chamber wherein said sample contains a fluorescent dye; c) illuminating said sample with excitation light; d) scanning the sample with said instrument to detect the fluorescence from said sample; e) measuring fluorescence intensity values in cell-free locations within a first area of interest having a size, A, and a first thickness; f) extrapolating to an integrated fluorescence intensity, I, from the first area of interest that could be expected under cell-free conditions; g) determining the first thickness, d, within the first area of interest by utilizing any known method for determining a liquid sample height; h) measuring an integrated fluorescence intensity, Icell, in said first area of interest, including all cells in this area; i) measuring fluorescence intensity values in cell-free locations within a second area of interest having a size, Acal=A, and a second thickness; j) extrapolating to an integrated fluorescence intensity, Ical, from the second area of interest that could be expected under cell-free conditions; k) determining the second thickness, dcal, within said second area of interest by utilizing any known method for determining a liquid sample height; l) using the quantities I, Icell, Ical, d, dcal, to calculate the HCT value of the sample by means of an equation that contains pairs of differences of integrated fluorescence intensities; and m) obtaining the HCT value of the sampler with said calibrated blood analyzer.