Method and apparatus for determination of hemoglobin content of individual red blood cells
AssigneeCoulter International Corp.
InventorsRobert Stewart Frank, James Lynn Wyatt
Life of this patent
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Abstract
This invention is related to an apparatus and method to determine the hemoglobin concentration of individual red blood cells by measuring the radio frequency resistance (RF) and direct current (DC) resistance resulting during the flow of the cells through a measurement aperture. The hemoglobin concentration of the cell is determined using the ratio of these two resistances. This determination can be made using a focused flow cell and a non-focused flow cell. In addition, the determination can be made with red blood cells which are either in their native, deformable state or with red blood cells that have been isovolumetrically sphered.
Claims20
A method to determine the hemoglobin concentration of individual red blood cells comprising the steps of
- a. entraining red blood cells of a blood sample into a stream of spaced apart, individual red blood cells in an electrolytic liquid,
- b. measuring low frequency electrical resistance of the electrolytic liquid within an aperture, including measuring a change in the electrical resistance caused by the passing of each of the red blood cells of the stream through the aperture, and deriving a corresponding first pulse signal for each red blood cell having an amplitude representative of the change in the electrical resistance caused by the passing of each red blood cell through the aperture,
- c. measuring radio frequency (RF) resistance of the electrolytic liquid within the aperture, including measuring a change in the radio frequency resistance caused by the passing of each of the red blood cells of the stream through the aperture, and deriving a corresponding second pulse signal for each red blood cell having an amplitude representative of the change in the radio frequency resistance caused by the passing of each red blood cell through the aperture,
- d. determining a shape for each red blood cell, and
- e. calculating the hemoglobin concentration of each of the red blood cells of the stream from a ratio of the corresponding second pulse signal to first pulse signal and the shape of the red blood cells.
An apparatus for measuring the hemoglobin concentration of individual red blood cells comprising:
- a. means for entraining red blood cells of a blood sample into a stream of spaced apart, individual red blood cells in an electrolyte liquid,
- b. resistance measuring means for measuring low frequency electrical resistance of the electrolytic liquid within an aperture, including measuring a change in the electrical resistance caused by the passing of each of the red blood cells of the stream through the aperture, and deriving a corresponding first pulse signal for each red blood cell having an amplitude representative of the change in the electrical resistance caused by the passing of each red blood cell through the aperture,
- c. radio frequency measuring means for measuring radio frequency (RF) resistance of the electrolytic liquid within the aperture, including measuring a change in the radio frequency resistance caused by the passing of each of the red blood cells of the stream through the aperture, and a corresponding second pulse signal for each red blood cell having an amplitude representative of the change in the radio frequency resistance caused by the passing of each red blood cell through the aperture,
- d. means for determining a shape for each red blood cell, and
- e. means for calculating the hemoglobin concentration of each of the red blood cells of the stream from a ratio of the corresponding second pulse signal to first pulse signal and the shape of the red blood cells.
Dependencies are inferred from the claim text.