Patent ID: 7790464

Claim:
A system for determining cell-free hemoglobin concentration within a sample containing at least one cell-free hemoglobin derivative and at least one cellular hemoglobin derivatives contained within erythrocytes, the system comprising: a light source configured to emit light; a sample block containing the sample and configured to allow the light to pass through the sample wherein, a first portion of the light, having a wavelength of about 390-460 nm, is absorbed by the cell-free hemoglobin derivatives, and a second portion of the light, having a wavelength of about 390-460 nm, is absorbed by the cellular hemoglobin derivatives contained within erythrocytes; at least one absorption detector configured to determine the light absorption of the sample block containing the sample, within a wavelength range of about 390-460 nm, and to generate a flattened spectra of cellular hemoglobin derivatives contained within erythrocytes and a non-flattened spectra of cell-free hemoglobin derivatives; and a processor configured to use data from the absorption detector to compare the flattened spectra of cellular hemoglobin derivatives contained within erythrocytes to the non-flattened spectra of cell free hemoglobin derivatives determined from the change in the light absorption of the sample within a wavelength range of 390-460 nm, and thereby determine the cell free hemoglobin concentration within the sample.