Method and apparatus for determining hemoglobin based parameters in an unlysed blood sample

Abstract

A method and apparatus for determining hemoglobin concentration is provided. A method aspect includes the steps of: a) depositing an unlysed, substantially undiluted blood sample into an analysis chamber adapted to quiescently hold the sample for analysis; b) imaging the sample in a region of the analysis chamber where the height of the chamber is no more than about twenty microns (20μ) or no less than about two microns (2μ), to produce image signals representative of the optical density of the imaged region; c) determining a sample representative optical density value using the image signals representative of the optical density of the imaged region; and d) determining the hemoglobin concentration of the sample using the sample representative optical density value.

What is claimed: 
     
         1 . A method for determining hemoglobin concentration of a blood sample, comprising:
 depositing an unlysed, substantially undiluted blood sample into an analysis chamber adapted to quiescently hold the sample for analysis, the chamber defined by an interior surface of a first panel, and an interior surface of a second panel, wherein both panels are transparent, and which chamber has a height extending between the interior surface of the first panel and the interior surface of the second panel;   using an analyzer having at least one processor, which at least one processor is in communication with at least one light source, at least one light detector, and with a memory device storing executable instructions, which instructions when executed cause the at least one processor to:
 control the at least one light source to illuminate at least a portion of the sample residing within a region of the analysis chamber where the height of the chamber is no more than about twenty microns (20μ) and not less than about two microns (2μ), and receive image signals representative of an optical density (OD) of the illuminated sample portion from the at least one light detector, which illuminated sample portion includes non-red blood cell constituents; 
 determine a sample representative OD value using the image signals representative of the OD of the sample within the illuminated sample portion; and 
 determine the hemoglobin concentration of the sample using the sample representative optical density value. 
   
     
     
         2 . The method of  claim 1 , wherein the image signals representative of the OD of the illuminated sample portion are representative of OD on a per image unit basis within the imaged region. 
     
     
         3 . The method of  claim 2 , wherein the image unit is a pixel. 
     
     
         4 . The method of  claim 1 , wherein the interior surface of the first panel and the interior surface of the second panel are substantially parallel each other. 
     
     
         5 . The method of  claim 1 , wherein the chamber height is about four microns (4μ). 
     
     
         6 . The method of  claim 1 , wherein the at least one light source emits light at a single peak wavelength. 
     
     
         7 . The method of  claim 6 , wherein the instructions that cause the at least one processor to determine the sample representative OD value further include instructions to determine per image unit OD values of the illuminated sample portion, and statistically analyze the per image unit OD values to determine the sample representative optical density value. 
     
     
         8 . The method of  claim 6 , wherein the instructions that cause the at least one processor to determine the hemoglobin concentration of the sample include directly or indirectly using empirical data with the sample representative OD value to determine the hemoglobin concentration of the sample, which empirical data includes OD values correlated to hemoglobin concentration values. 
     
     
         9 . The method of  claim 6 , wherein the instructions that cause the at least one processor to determine the hemoglobin concentration of the sample include directly or indirectly using a theoretical model with the sample representative OD value to determine the hemoglobin concentration of the sample. 
     
     
         10 . The method of  claim 6 , wherein the instructions that cause the at least one processor to determine the hemoglobin concentration of the sample include directly or indirectly using an analytical model with the sample representative OD value to determine the hemoglobin concentration of the sample. 
     
     
         11 . The method of  claim 1 , wherein the instructions that cause the at least one processor to determine the sample representative OD value further include instructions to determine per image unit OD values of the illuminated sample portion, and statistically analyze the per image unit OD values to determine the sample representative OD value. 
     
     
         12 . The method of  claim 11 , wherein the instructions that cause the at least one processor to determining the hemoglobin concentration of the sample includes directly or indirectly using empirical data with the sample representative OD value to determine the hemoglobin concentration of the sample, which empirical data includes OD values correlated to hemoglobin concentration values. 
     
     
         13 . An apparatus for determining hemoglobin concentration within an unlysed, substantially undiluted whole blood sample, which sample includes non-red blood cell constituents, comprising:
 an analysis chamber configured to quiescently hold the sample for analysis, the chamber defined by an interior surface of a first panel, and an interior surface of a second panel, wherein both panels are transparent, and which chamber has a height extending between the interior surface of the first panel and the interior surface of the second panel, which height is no more than about twenty microns (20μ) and not less than about two microns (2μ);   at least one light source;   at least one light detector; and   an analyzer having at least one processor, which at least one processor is in communication with the at least one light source, the at least one light detector, and with a memory device storing executable instructions, which instructions when executed cause the at least one processor to:
 control the at least one light source to illuminate a region of the sample quiescently residing within the chamber, including emitting light that passes through the sample region, which sample region includes red blood cells and one or more non-red blood cells constituents, and to receive image signals from the at least one light detector, which image signals are representative of the emitted light that has passed through the sample region; 
 determine a sample representative optical density (OD) value using the image signals; and 
 determine the hemoglobin concentration of the region of the sample using the sample representative OD value. 
   
     
     
         14 . The apparatus of  claim 13 , wherein the instructions cause the at least one processor to determine a plurality of OD values on a per image unit basis within the illuminated sample region, and to determine the sample representative OD value using the per image unit optical density values. 
     
     
         15 . The apparatus of  claim 14 , wherein the instructions cause the at least one processor to statistically analyze the per image unit OD values to determine the sample representative OD value. 
     
     
         16 . The apparatus of  claim 13 , wherein the instructions cause the at least one processor to determine the hemoglobin concentration of the illuminated sample region using empirical data and the sample representative OD value. 
     
     
         17 . A method for determining a red blood cell distribution width (RDW) of a blood sample, comprising:
 depositing an unlysed, substantially undiluted blood sample into an analysis chamber adapted to quiescently hold the sample for analysis;   using an analyzer having at least one processor, which at least one processor is in communication with at least one light source, at least one light detector, and with a memory device storing executable instructions, which instructions when executed cause the at least one processor to:
 control the at least one light source to illuminate at least a portion of the sample residing within a region of the analysis chamber, and receive image signals representative of the optical density (OD) of the illuminated sample portion from the at least one light detector, which illuminated sample portion includes non-red blood cell constituents; 
 determine a sample representative OD value using the image signals representative of the OD of the sample within the illuminated sample region; and 
 determine the RDW of the sample using the sample representative OD value. 
   
     
     
         18 . The method of  claim 17 , wherein the instructions that cause the at least one processor to determine the RDW of the sample further include instructions that cause the at least one processor to determine a cell volume value for each of a clinically acceptable number of red blood cells, a standard deviation of the determined red blood cell volumes, and a mean red blood cell volume value for the clinically acceptable number of red blood cells.