Hemoglobin sensor

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.

What is claimed is:  
     
         1 . A device for measuring an amount of hemoglobin in a sample, the device comprising an electrochemical cell having a sensing chamber, a first electrode, a second electrode wherein the second electrode is a distance of less than about 500 microns from the first electrode, an aperture for admitting the sample into the sensing chamber, 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.  
     
     
         2 . The device of  claim 1 , wherein the device may only be used for a single test.  
     
     
         3 . The device of  claim 1 , wherein the first electrode comprises a sensing electrode.  
     
     
         4 . The device of  claim 1 , wherein the first electrode comprises a material selected from the group consisting of platinum, palladium, carbon, indium oxide, tin oxide, gold, iridium, copper, steel, silver, and mixtures thereof.  
     
     
         5 . The device of  claim 1 , wherein the first electrode is formed by a technique selected from the group consisting of sputtering, vapor coating, screen printing, thermal evaporation, ink jet printing, ultrasonic spraying, slot coating, gravure printing and lithography.  
     
     
         6 . The device of  claim 1 , wherein the second electrode comprises a counter electrode.  
     
     
         7 . The device of  claim 1 , wherein the second electrode comprises a metal in contact with a metal salt.  
     
     
         8 . The device of  claim 7 , wherein the metal in contact with a metal salt is selected from the group consisting of silver in contact with silver chloride, silver in contact with silver bromide, silver in contact with silver iodide, mercury in contact with mercurous chloride, and mercury in contact with mercurous sulfate.  
     
     
         9 . The device of  claim 7 , the electrochemical cell further comprising a third electrode.  
     
     
         10 . The device of  claim 9 , wherein the third electrode comprises a reference electrode.  
     
     
         11 . The device of  claim 10 , wherein the third electrode comprises a metal in contact with a metal salt.  
     
     
         12 . The device of  claim 11 , wherein the metal in contact with the metal salt is selected from the group consisting of silver in contact with silver chloride, silver in contact with silver bromide, silver in contact with silver iodide, mercury in contact with mercurous chloride, and mercury in contact with mercurous sulfate.  
     
     
         13 . The device of  claim 1 , wherein the second electrode comprises a reference electrode.  
     
     
         14 . The device of  claim 1 , wherein the reagent is selected from the group consisting of dichromate, vanadium oxides, permanganate, electroactive organometallic complexes, quinones, and dichlorophenolindophenol.  
     
     
         15 . The device of  claim 1 , wherein the reagent comprises ferricyanide.  
     
     
         16 . The device of  claim 1 , the sensing chamber further comprising a buffer, wherein the buffer is contained within the sensing chamber.  
     
     
         17 . The device of  claim 16 , wherein the buffer is selected from the group consisting of phosphates, carbonates, alkali metal salts of mellitic acid, and alkali metal salts of citric acid.  
     
     
         18 . The device of  claim 1 , further comprising a red blood cell lysing agent.  
     
     
         19 . The device of  claim 18 , wherein the lysing agent is selected from the group consisting of ionic detergents, nonionic detergents, proteolytic enzymes, and lipases.  
     
     
         20 . The device of  claim 18 , wherein the lysing agent comprises saponin.  
     
     
         21 . The device of  claim 18 , wherein the lysing agent is selected from the group consisting of sodium dodecyl sulfate, cetyl trimethylammonium bromide, and polyethoxylated octylphenol.  
     
     
         22 . The device of  claim 1 , wherein the sample comprises fluid whole blood.  
     
     
         23 . The device of  claim 1 , the sensing chamber further comprising a support, the support contained within the sensing chamber.  
     
     
         24 . The device of  claim 23 , wherein the support is a material selected from the group consisting of mesh, nonwoven sheet, fibrous filler, macroporous membrane, sintered powder, and combinations thereof.  
     
     
         25 . The device of  claim 23 , wherein the reagent is contained within or supported on the support.  
     
     
         26 . The device of  claim 23 , further comprising a buffer, wherein the buffer is contained within or supported on the support.  
     
     
         27 . The device of  claim 23 , wherein the lysing agent is contained within or supported on the support.  
     
     
         28 . The device of  claim 1 , wherein the second electrode is mounted in opposing relationship to the first electrode.  
     
     
         29 . The device of  claim 1 , wherein the second electrode is at a distance of less than about 150 microns from the first electrode.  
     
     
         30 . The device according to  claim 1 , wherein the second electrode is at a distance of from about 50 microns to about 150 microns from the first electrode.  
     
     
         31 . The device of  claim 1 , further comprising an interface for communication with a meter.  
     
     
         32 . The device of  claim 31 , wherein the interface communicates a voltage or a current.  
     
     
         33 . The device of  claim 1 , wherein the electrochemical cell comprises a thin layer electrochemical cell.