Correlation of Alternative Site Blood and Interstitial Fluid Glucose Concentrations to Venous Glucose Concentration

Abstract

The invention relates to a method for calibrating an analyte-measurement device that is used to evaluate a concentration of analyte in bodily fluid at or from a measurement site in a body. The method involves measuring a concentration, or calibration concentration, of an analyte in blood from an “off-finger” calibration site, and calibrating the analyte-measurement device based on that calibration concentration. The invention also relates to a device, system, or kit for measuring a concentration of an analyte in a body, which employs a calibration device for adjusting analyte concentration measured in bodily fluid based on an analyte concentration measured in blood from an “off-finger” calibration site.

1 . A method, comprising:
 obtaining, using one or more processors, an analyte related signal from an analyte sensor in fluid contact with interstitial fluid;   obtaining, using the one or more processors, a reference signal from a reference sensor in fluid contact with a blood sample;   confirming, using the one or more processors, a deviation between the analyte related signal and the reference signal does not exceed a predetermined time lag between the analyte related signal from the analyte sensor and the reference signal; and   outputting, using the one or more processors, the analyte related signal based upon the confirmation.   
     
     
         2 . The method of  claim 1  wherein the predetermined time lag ranges from about 2 minutes to 30 minutes. 
     
     
         3 . The method of  claim 2  wherein the predetermined time lag is less that about 15 minutes. 
     
     
         4 . The method of  claim 1  wherein the analyte sensor exhibits linearity at high and low glucose values between physiologically relevant glucose range. 
     
     
         5 . The method of  claim 1  wherein at least 98% of the analyte related signals from the analyte sensor are within clinically accurate or clinically acceptable range. 
     
     
         6 . The method of  claim 1  wherein the blood sample includes a blood sample from a forearm. 
     
     
         7 . The method of  claim 1  wherein outputting the analyte related signal includes displaying a glucose value associated with the analyte related signal. 
     
     
         8 . The method of  claim 1  including calibrating, using the one or more processors, the analyte sensor. 
     
     
         9 . The method of  claim 1  including confirming, using the one or more processors, the accuracy of the analyte related signal based on the reference signal. 
     
     
         10 . An apparatus, comprising:
 one or more processors; and   a memory coupled to the one or more processors, the memory storing instructions which, when executed by the one or more processors, cause the one or more processors to receive an analyte related signal from an analyte sensor in fluid contact with interstitial fluid, receive a reference signal from a reference sensor in fluid contact with a blood sample, confirm a deviation between the analyte related signal and the reference signal does not exceed a predetermined time lag between the analyte related signal from the analyte sensor and the reference signal, and output the analyte related signal based upon the confirmation.   
     
     
         11 . The apparatus of  claim 10  wherein the predetermined time lag ranges from about 2 minutes to 30 minutes. 
     
     
         12 . The apparatus of  claim 11  wherein the predetermined time lag is less that about 15 minutes. 
     
     
         13 . The apparatus of  claim 10  wherein the analyte sensor exhibits linearity at high and low glucose values between physiologically relevant glucose range. 
     
     
         14 . The apparatus of  claim 10  wherein at least 98% of the analyte related signals from the analyte sensor are within clinically accurate or clinically acceptable range. 
     
     
         15 . The apparatus of  claim 10  wherein the blood sample includes a blood sample from a forearm. 
     
     
         16 . The apparatus of  claim 10  including an output unit operatively coupled to the one or more processors, the output unit configured to display a glucose value associated with the analyte related signal. 
     
     
         17 . The apparatus of  claim 10  wherein the memory storing instructions which, when executed by the one or more processors, causes the one or more processors to calibrate the analyte sensor. 
     
     
         18 . The apparatus of  claim 10  wherein the memory storing instructions which, when executed by the one or more processors, causes the one or more processors to confirm the accuracy of the analyte related signal based on the reference signal.