Abstract: A method and apparatus that allows accurate spectrophotometric determination of the concentrations of various hemoglobin species in whole undiluted blood. The invention employs 1) an optical apparatus designed to maximize the true optical absorbance of whole blood and to minimize the effects of light scattering on the spectrophotometric measurements of the concentrations of various constituent components, and 2) methods to correct the hemoglobin concentration measurements for light scattering and for the effects of the finite bandwidth of the substantially monochromatic light. In the optical apparatus optical parameters, such as sample thickness, detector size and shape, sample-to-detector distance, wavelengths, monochromicity, and maximum angle of light capture by detector, are selected so as to minimize the contribution of light scattering to maximize the contribution of true optical absorbance.

Abstract: A method and apparatus which allow accurate spectrophotometric determinations of the concentrations of various hemoglobin species in whole blood without hemolysis or dilution. To overcome the complex optical properties of whole blood, the invention employs 1) an optical apparatus designed to maximize the true optical absorbance of whole blood and to minimize the effects of light scattering on the spectrophotometric measurements of the concentrations of various constituent components, and 2) methods to correct the hemoglobin concentration measurements for light scattering and for the effects of the finite bandwidth of the substantially monochromatic light.

Abstract: A method and apparatus that allows accurate spectrophotometric determination of the concentrations of various hemoglobin species in whole undiluted blood. The invention employs 1) an optical apparatus designed to maximize the true optical absorbance of whole blood and to minimize the effects of light scattering on the spectrophotometric measurements of the concentrations of various constituent components, and 2) methods to correct the hemoglobin concentration measurements for light scattering and for the effects of the finite bandwidth of the substantially monochromatic light. In the optical apparatus optical parameters, such as sample thickness, detector size, sample-to-detector distance, wavelengths, monochromicity, and maximum angle of light capture by detector, are selected so as to minimize the contribution of light scattering and to maximize the contribution of true optical absorbance.

Abstract: A method and apparatus that allows accurate spectrophotometric determination of the concentrations of various hemoglobin species in whole undiluted blood. The invention employs 1) an optical apparatus designed to maximize the true optical absorbance of whole blood and to minimize the effects of light scattering on the spectrophotometric measurements of the concentrations of various constituent components, and 2) methods to correct the hemoglobin concentration measurements for light scattering and for the effects of the finite bandwidth of the substantially monochromatic light. In the optical apparatus optical parameters, such as sample thickness, detector size, sample-to-detector distance, wavelengths, monochromicity, and maximum angle of light capture by detector, are selected so as to minimize the contribution of light scattering and to maximize the contribution of true optical absorbance.

Abstract: A method and apparatus that allows accurate spectrophotometric determination of the concentrations of various hemoglobin species in whole blood without hemolysis or dilution. To overcome the complex optical properties of whole blood, the invention employs 1) an optical apparatus designed to maximize the true optical absorbance of whole blood and to minimize the effects of light scattering on the spectrophotometric measurements of the concentrations of various constituent components, and 2) methods to correct the hemoglobin concentration measurements for light scattering and for the effects of the finite bandwidth of the substantially monochromatic light.

Abstract: An oximeter that measures both the total hemoglobin concentration in whole, undiluted blood and the percentage of the hemoglobin saturated with oxygen. The oximeter uses red and infrared light-emitting diodes to illuminate a capillary tube filled with a sample of whole, undiluted blood. Light scattered by the blood travels a short distance down the length of the capillary tube and reaches a photodetector, the output of which is amplified, digitized, and fed to a microprocessor. The microprocessor computes the total hemoglobin concentration as a nonlinear monotonic function of the infrared light intensity. Oxyhemoglobin saturation is computed from the ratio of the logarithms of the intensities of red and infrared light. The invention provides a measurement of oxygen saturation without calibration shifts present in other oximeters due to fluctuations in total hemoglobin concentration.