Method and apparatus for using alternative site glucose determinations to calibrate and maintain noninvasive and implantable analyzers

Abstract

A method and apparatus for calibrating noninvasive or implantable glucose analyzers uses either alternative invasive glucose determinations or noninvasive glucose determinations for calibrating noninvasive or implantable glucose analyzers. Use of an alternative invasive or noninvasive glucose determination in the calibration allows minimization of errors due to sampling methodology, and spatial and temporal variations that are built into the calibration model. An additional embodiment uses statistical correlations between noninvasive and alternative invasive glucose determinations and traditional invasive glucose determinations to adjust noninvasive or alternative invasive glucose concentrations to traditional invasive glucose concentrations. The invention provides a means for calibrating on the basis of glucose determinations that reflect the matrix observed and the variable measured by the analyzer more closely. A glucose analyzer couples an invasive fingerstick meter to a noninvasive glucose analyzer for calibration, validation, adaptation, and safety check of the calibration model embodied in the noninvasive analyzer.

1 . A method for accounting for sampling-related differences in blood glucose measurements, comprising the steps of: 
 providing a transform that models a relationship between sets of glucose measurements, wherein each set comprises samples collected in a different manner; and    converting subsequent measurements according to said transform.    
     
     
         2 . The method of  claim 1 , wherein said sets of glucose measurements comprise either of a set of alternate invasive measurements and a set of traditional invasive measurements, or a set of noninvasive and a set of traditional invasive measurements.  
     
     
         3 . The method of  claim 2 , wherein said relationship comprises any of: 
 a magnitude difference;    a lag;    a phase difference; and    a width difference.    
     
     
         4 . The method of  claim 3 , wherein said transform embodies an algorithm, said algorithm comprising the step of: 
 dividing a set of measurements by said magnitude difference.    
     
     
         5 . The method of  claim 3 , wherein said transform embodies an algorithm, said algorithm comprising the step of: 
 subtracting said lag from a set of measurements.    
     
     
         6 . The method of  claim 3 , wherein said transform embodies an algorithm, said algorithm comprising the step of: 
 subtracting said phase difference from a set of measurements.    
     
     
         7 . The method of  claim 3 , wherein said transform embodies an algorithm, said algorithm comprising the step of: 
 adjusting a set of alternative invasive glucose concentrations with said width difference.    
     
     
         8 . The method of  claim 2 , wherein said sets of measurements are generated during periodic testing after a carbohydrate load.  
     
     
         9 . The method of  claim 2 , wherein subsequent measurements comprise any of: 
 single measurements; and    sets of measurements.    
     
     
         10 . The method of  claim 1 , wherein said step of converting subsequent measurements comprises the step of: 
 converting between traditional invasive measurements and alternative invasive measurements.    
     
     
         11 . The method of  claim 1 , wherein said step of converting subsequent measurements comprises the step of: 
 converting between noninvasive measurements predicted from a calibration based on alternative invasive measurements, and traditional invasive measurements.