Analyte detection devices and methods with hematocrit/volume correction and feedback control

Abstract

Disclosed are devices, arrangements and methods for quantifying the concentration of an analyte present in bodily fluid, including: an assay pad having at least one chemical reagent capable of producing a detectable signal in the form of a reaction spot upon reaction with the analyte; a light source; a detector array; a processor; and a memory in communication with the processor, the memory comprising: (a) at least one value indicative of one or more of: (i) the level of hematocrit contained in the sample; (ii) the volume of the sample applied to the assay pad; or (iii) imperfections present in the reaction spot; and (b) at least one algorithm for calculating the concentration of the analyte contained in the sample.

1 . An arrangement for measuring the concentration of an analyte contained in a sample of body fluid, the arrangement comprising: 
 an assay pad comprising at least one chemical reagent capable of producing a detectable signal in the form of a reaction spot formed upon reaction with the analyte;    a light source;    a detector array;    a processor; and    a memory in communication with the processor, the memory comprising: 
 (a) at least one value indicative of one or more of: 
 (i) the level of hematocrit contained in the sample;  
 (ii) the volume of the sample applied to the assay pad; or  
 (iii) imperfections present in the reaction spot; and  
 
 (b) at least one algorithm for calculating the concentration of the analyte contained in the sample.  
   
     
     
         2 . The arrangement of  claim 1 , wherein the analyte comprises glucose and the body fluid comprises blood.  
     
     
         3 . The arrangement of  claim 1 , wherein the detector array is a linear array.  
     
     
         4 . The arrangement of  claim 1 , wherein the detector array comprises at least one of a linear array, a polar array, and an area array.  
     
     
         5 . The arrangement of  claim 1 , wherein the detector array comprises a plurality of detector elements, the detector elements comprising CMOS, CCD, photodiode, infrared, fluorescent, ultraviolet or electrochemical elements.  
     
     
         6 . The arrangement of  claim 1 , further comprising at least one catalyst device.  
     
     
         7 . The arrangement of claim δ, wherein the at least one catalyst device comprises at least one of a vacuum pump, a vibration motor and a heating element.  
     
     
         8 . The arrangement of  claim 1 , wherein the at least once catalyst device is constructed and arranged to be responsive to control signals, the control signals based on sample volume calculations.  
     
     
         9 . The arrangement of  claim 5 , wherein at least a portion of the plurality of detector elements are not in optical registry with the reagent spot and are configured and arranged to analyze one or more of a control solution having a known concentration of analyte introduced onto an area of the assay pad that is different from the area of the reagent spot, a standard color producing a known signal, and calibration information specific to the lot of the assay pad.  
     
     
         10 . The arrangement of  claim 1 , wherein the memory comprises at least one look-up table, and the at least one value is stored in the at least one look-up table.  
     
     
         11 . The arrangement of  claim 1 , wherein the memory comprises a formula for deriving a corrected signal, the formula comprising:  
       
         
        
         R 
         c 
         =F 
         x 
         ×R  
        
       
       where R c  is the corrected signal, F x  is the at least one value indicative of the level of hematocrit or the volume of the sample.  
     
     
         12 . The arrangement of  claim 1 , further comprising a needle having a first end configured to pierce the skin, and a second end in fluid communication with the assay pad.  
     
     
         13 . An analyte monitoring device comprising the arrangement of  claim 1 .  
     
     
         14 . The analyte monitoring device of  claim 13 , wherein the arrangement comprises a plurality of assay pads and a plurality of needles, thereby enabling the performance of a plurality of analyte concentration measurements.  
     
     
         15 . The analyte monitoring device of  claim 13 , further comprising a band for attaching the device to the body of the user.  
     
     
         16 . A method of measuring the content of analyte contained in a sample of body fluid, the method comprising: 
 providing an assay pad comprising at least one chemical reagent;    introducing a sample onto the assay pad;    producing a detectable signal in the form of a reaction spot formed upon reaction of the at least one chemical reagent with the analyte;    generating a signal based on light reflected off the assay pad;    calculating at least one value indicative to one or more of: 
 (i) the level of hematocrit contained in the sample;  
 (ii) the volume of the sample applied to the assay pad; or  
 (iii) imperfections present in the reaction spot; and  
   calculating the concentration of analyte contained in the sample by factoring in the at least one value.    
     
     
         17 . The method of  claim 16 , wherein the analyte comprises glucose and the body fluid comprises blood.  
     
     
         18 . The method of  claim 16 , wherein the step of generating a signal based on light reflected off the assay pad comprises providing a detector array in optical registry with at least the reaction spot on the assay pad.  
     
     
         19 . The method of  claim 18 , wherein the detector array comprises at least one of a linear array, a polar array, and an area array.  
     
     
         20 . The method of  claim 19 , wherein the detector array comprises a plurality of detector elements, the detector elements comprising CMOS, CCD, photodiode, infrared, fluorescent, ultraviolet or electrochemical elements.  
     
     
         21 . The method of  claim 16 , further comprising applying at least one catalyst to the surface of the skin of the user to facilitate sample acquisition.  
     
     
         22 . The method of  claim 21 , wherein the at least one catalyst comprises at least one of a vacuum pressure, positive pressure, vibration, and heat.  
     
     
         23 . The method of  claim 21 , wherein the step of applying at least once catalyst comprises controlling application of the catalyst with a control signal based on sample volume calculations.  
     
     
         24 . The method of  claim 20 , further comprising using at least a portion of the plurality of detector elements not in optical registry with the reagent spot to analyze one or more of a control solution having a known concentration of analyte introduced onto an area of the assay pad that is different from the area of the reagent spot, reading a standard color producing a known signal, and reading calibration information specific to the lot of the assay pad.  
     
     
         25 . The method of  claim 16 , wherein the step of calculating comprises acquiring the at least one value from at least one look-up table.  
     
     
         26 . The method of  claim 16 , wherein the step of calculating the concentration of analyte comprises deriving a corrected signal from the formula comprising:  
       
         
        
         R 
         c 
         =F 
         x 
         ×R  
        
       
       where R c , is the corrected signal, F x  is the at least one value indicative of the level of hematocrit or the volume of the sample.  
     
     
         27 . The method of  claim 16 , further comprising piercing the skin of the user with a first end of a needle, and transporting a sample of blood through a second end of the needle to the assay pad.  
     
     
         28 . An arrangement for measuring the concentration of an analyte contained in a sample of body fluid, the arrangement comprising: 
 an assay pad comprising at least one chemical reagent capable of producing a detectable signal in the form of a reaction spot formed upon reaction with the analyte;    a light source;    a detector array;    a processor;    a memory in communication with the processor; and    at least one catalyst device constructed and arranged to be responsive to control signals.    
     
     
         29 . The arrangement of  claim 28 , wherein the detector array comprises a linear array of detector elements, the detector elements comprising CMOS, CCD, photodiode, infrared, fluorescent, ultraviolet or electrochemical elements.  
     
     
         30 . The arrangement of  claim 28 , wherein the at least one catalyst device comprises at least one of a vacuum pump, a vibration motor and a heating element.  
     
     
         31 . The arrangement of  claim 28 , wherein the at least one catalyst device is constructed and arranged to be responsive to control signals derived from a signal based on light reflected off the assay pad and detected by the detector array.  
     
     
         32 . The arrangement of  claim 28 , wherein a lease one catalyst device is constructed and arranged to be responsive to control signals derived from a signal based on imaging of a surface on the skin of the user.  
     
     
         33 . The arrangement of  claim 28 , wherein the detector array, processor and memory are constructed and arranged to predict sample volume be delivered to the assay pad.  
     
     
         34 . The arrangement of  claim 33 , wherein the sample volume to be delivered to the assay pad is predicted based at least in part on a signal generated by light reflected off the assay pad and detected by the detector array.  
     
     
         35 . An integrated meter comprising: 
 at least one piercing element;    at least one actuation member; and    the arrangement of  claim 1 .    
     
     
         36 . An integrated meter comprising: 
 at least one piercing element;    at least one actuation member; and    the arrangement of  claim 28.