Hemoglobin sensor
First Claim
1. A device for measuring an amount of hemoglobin in a fluid whole blood sample, the whole blood sample containing red blood cells, the red blood cells containing hemoglobin, the device comprising an electrochemical cell having a sensing chamber, a first electrode, a second electrode wherein the second electrode is mounted in opposing relationship a distance of less than about 500 microns from the first electrode, an aperture for admitting the sample into the sensing chamber, a red blood cell lysing agent, and a reagent contained within the sensing chamber wherein the reagent is capable of being reduced by hemoglobin to generate an electrical signal indicative of the amount of hemoglobin, wherein the device further comprises means for applying a positive potential to the first electrode;
- means for measuring a current generated by reaction of the reagent and hemoglobin;
means for analyzing the current to give a result, the result comprising a time required for substantial lysis of the red blood cells or a derived final value for the current;
means for calculating a percentage of the reaction completed as a function of time based on the result of the analyzing step;
means for reversing the potential on the first electrode;
means for measuring a transient current; and
means for determining a diffusion coefficient and a concentration of a reduced form of the reagent based on the transient current.
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Abstract
The present invention relates to a device and method for measuring hemoglobin in a fluid sample. The device comprises a disposable electrochemical cell, such as a thin layer electrochemical cell, containing a reagent capable of being reduced by hemoglobin. A suitable fluid sample that may be analyzed according the present invention is whole blood. If the hemoglobin to be analyzed is present in red blood cells, a lysing agent may be added to the sample to release the hemoglobin prior to analysis.
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Citations
66 Claims
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1. A device for measuring an amount of hemoglobin in a fluid whole blood sample, the whole blood sample containing red blood cells, the red blood cells containing hemoglobin, the device comprising an electrochemical cell having a sensing chamber, a first electrode, a second electrode wherein the second electrode is mounted in opposing relationship a distance of less than about 500 microns from the first electrode, an aperture for admitting the sample into the sensing chamber, a red blood cell lysing agent, and a reagent contained within the sensing chamber wherein the reagent is capable of being reduced by hemoglobin to generate an electrical signal indicative of the amount of hemoglobin, wherein the device further comprises means for applying a positive potential to the first electrode;
- means for measuring a current generated by reaction of the reagent and hemoglobin;
means for analyzing the current to give a result, the result comprising a time required for substantial lysis of the red blood cells or a derived final value for the current;
means for calculating a percentage of the reaction completed as a function of time based on the result of the analyzing step;
means for reversing the potential on the first electrode;
means for measuring a transient current; and
means for determining a diffusion coefficient and a concentration of a reduced form of the reagent based on the transient current. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30)
- means for measuring a current generated by reaction of the reagent and hemoglobin;
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31. A method for measuring an amount of hemoglobin in a fluid whole blood sample, the whole blood sample containing red blood cells, the red blood cells containing hemoglobin, wherein the method comprises:
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providing a device comprising an electrochemical cell having a sensing chamber, a first electrode, a second electrode wherein the second electrode is mounted in opposing relationship a distance of less than about 500 microns from the first electrode, an aperture for admitting the sample into the sensing chamber;
a reagent contained within the sensing chamber and capable of being reduced by hemoglobin; and
a red blood cell lysing agent contained within the sensing chamber;
placing the whole blood sample in the sensing chamber, whereby the lysing agent contained within the sensing chamber releases hemoglobin from the red blood cells, whereby the hemoglobin thus released reduces the reagent; and
obtaining an electrochemical measurement indicative of an amount of hemoglobin present in the whole blood sample, wherein the step of obtaining an electrochemical measurement comprises;
applying a positive potential to the first electrode;
measuring a current generated by reaction of the reagent and hemoglobin;
analyzing the current to give a result, the result comprising a time required for substantial lysis of the red blood cells or a derived final value for the current;
calculating a percentage of the reaction completed as a function of time based on the result of the analyzing step;
reversing the potential on the first electrode;
measuring a transient current; and
determining a diffusion coefficient and a concentration of a reduced form of the reagent based on the transient current. - View Dependent Claims (32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45)
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46. A method of manufacture of a device for determining an amount of hemoglobin in a fluid whole blood sample, the whole blood sample comprising red blood cells, the red blood cells comprising hemoglobin, the device comprising an electrochemical cell having a sensing chamber, a first electrode, a second electrode, an aperture for admitting the sample into the sensing chamber, a red blood cell lysing agent, and a reagent contained within the sensing chamber, wherein the reagent is capable of being reduced by hemoglobin to generate an electrical signal indicative of the amount of hemoglobin in the sample, the method comprising:
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forming an aperture extending through a sheet of electrically resistive material, the aperture defining a side wall of the sensing chamber;
mounting a first layer having a first electrode to a first side of the sheet and extending over the aperture whereby to define a first sensing chamber end wall, the first electrode facing the first side of the sheet;
mounting a second layer having a second electrode to a second side of the sheet and extending over the aperture whereby to define a second sensing chamber end wall in substantial overlying registration with the first layer, the second electrode facing the second side of the sheet, whereby the sheet and layers form a strip, and wherein the second electrode is mounted in opposing relationship a distance of less than about 500 microns from the first electrode;
providing an aperture in the strip to permit entry of sample into the sensing chamber;
providing a reagent capable of being reduced by hemoglobin, wherein the reagent is contained within the sensing chamber;
providing a red blood cell lysing agent, wherein the lysing agent is contained within the sensing chamber;
providing means for applying a positive potential to the first electrode;
means for measuring a current generated by reaction of the reagent and hemoglobin;
providing means for analyzing the current to give a result, the result comprising a time required for substantial lysis of red blood cells or a derived final value for the current;
providing means for calculating a percentage of the reaction completed as a function of time based on the result of the analyzing step;
providing means for reversing the potential on the first electrode;
providing means for measuring a transient current; and
providing means for determining a diffusion coefficient and a concentration of a reduced form of the reagent based on the transient current. - View Dependent Claims (47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66)
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Specification