Method for detecting a malfunction of a sensor for measuring an analyte concentration in vivo

Abstract

The invention relates to a method for detecting a malfunction of a sensor for measuring an analyte concentration in vivo, wherein a series of measurement signals is produced by means of the sensor, and a value of a noise parameter is continually determined from the measuring signals, the noise parameter indicating how severely the measurement is impaired by interference signals. According to the invention, continually determined values of the noise parameter are used to determine how quickly the noise parameter changes, and the rate of change of the noise parameter is evaluated to detect a malfunction.

1 - 15 . (canceled) 
     
     
         16 . A method for detecting a malfunction of a sensor for measuring an analyte concentration in vivo, comprising:
 producing a series of measuring signals, by means of the sensor;   determining successively a value of a noise parameter from the measuring signals, the noise parameter indicating how severely the measurement is impaired by interference signals;   determining the rate of change of the values of the noise parameter; and   analyzing the rate of change of the noise parameter in order to detect a malfunction.   
     
     
         17 . The method according to  claim 16 , wherein one value of a noise parameter each is determined for a pre-determined time interval. 
     
     
         18 . The method according to  claim 16 , wherein a recursive filter is used to continually determine a value of a noise parameter from the measuring signals. 
     
     
         19 . The method according to  claim 16 , wherein the rate of change of the noise parameter is analyzed by comparing it to a threshold value. 
     
     
         20 . The method according to  claim 19 , wherein the threshold value is changed during sensor operation as a function of a measuring result. 
     
     
         21 . The method according to  claim 20 , wherein the sensor comprises a working electrode, a counter-electrode, and a reference electrode, whereby the measuring result is based on a measurement of the electrical potential of the counter-electrode. 
     
     
         22 . The method according to  claim 19 , wherein, after detecting that a value of the rate of change exceeds the threshold value, at least one subsequent value of the rate of change is analyzed to check if the exceeding of the threshold value is significant. 
     
     
         23 . The method according to  claim 16 , wherein a warning signal is generated as a consequence of the detection of a malfunction. 
     
     
         24 . The method according to  claim 16 , wherein a malfunction that has been determined by the analysis of the rate of change is assigned to one of at least two classes. 
     
     
         25 . The method according to  claim 24 , wherein the assignment is made as a function of the rate of change and of at least one further parameter. 
     
     
         26 . The method according to  claim 16 , wherein the noise parameter characterizes the absolute intensity of the interference signals. 
     
     
         27 . The method according to  claim 16 , wherein multiple measuring signals are used to calculate one measuring value each and multiple measuring values are used to calculate one value of the noise parameter each. 
     
     
         28 . The method according to  claim 27 , wherein the measuring values are calculated by calculating the mean of multiple measuring signals. 
     
     
         29 . The method according to  claim 16 , wherein the rate of change of the noise parameter is determined on a smoothened series of values of the noise parameter. 
     
     
         30 . A method for detecting a malfunction of a sensor for measuring an analyte concentration in vivo, comprising:
 producing a series of measuring signals, by means of the sensor;   determining successively a value of a noise parameter from the measuring signals, the noise parameter indicating how severely the measuring signals are impaired by interference signals;   comparing the noise parameter to a threshold value in order to detect a malfunction; wherein   the threshold value is changed during sensor operation as a function of a measuring result.