Systems and methods for biosensor cross-calibration

Abstract

Embodiments provide for methods, systems, apparatus and computer readable media for calibrating an analyte sensor upon insertion into tissue of a subject based at least in part on parameters obtained from another analyte sensor already calibrated and previously inserted into the tissue of the subject. As an example, a method may include predicting a background current associated with the newly inserted sensor, subtracting the background current from a current measured by the newly inserted sensor, and converting the subtracted current to a glucose value, the converting based at least in part on the parameters obtained from the previously inserted analyte sensor. In this way, the newly inserted sensor may be calibrated without relying on actual blood-based analyte measurements, and accuracy and sensitivity of the newly inserted sensor may be improved.

What is claimed is: 
     
         1 . An apparatus for calibrating a biosensor inserted into tissue of a subject, comprising:
 a computing device including a processor, the processor storing instructions in non-transitory memory that, when executed, cause the processor to:   while a first sensor is inserted into the tissue of the subject, detect insertion of a second sensor into the tissue;   initiate a cross-calibration procedure of the second sensor responsive to the detecting, wherein in the cross-calibration procedure, the instructions, when executed, cause the processor to:
 obtain a first current from the first sensor and a second current from the second sensor, and convert the first current into a first analyte value; 
 in response to an indication that a predetermined condition is met for modeling a first non-glucose driven background current associated with the second sensor, predict the first non-glucose driven background current for the second sensor over a first time duration; 
 during the first time duration, subtract the first non-glucose driven background current from the second current to obtain a subtracted second current for the second sensor; and 
 convert the subtracted second current to a second analyte value. 
   
     
     
         2 . The apparatus of  claim 1 , wherein the instructions, when executed, cause the processor to predict the first non-glucose driven background current based on the second current measured prior to the predetermined condition being met, and at least in part on one or more of the first current or the first analyte value obtained prior to the predetermined condition being met. 
     
     
         3 . The apparatus of  claim 2 , wherein the instructions, when executed, cause the processor to predict the first non-glucose driven background current based on a previously generated pattern of background current changes learned over time from a plurality of other analyte sensors inserted into the subject at earlier times. 
     
     
         4 . The apparatus of  claim 1 , wherein:
 the indication that predetermined condition is met for modeling the first non-glucose driven background current occurs between one minute and sixty minutes after initiation of the cross-calibration procedure.   
     
     
         5 . The apparatus of  claim 4 , wherein the first time duration in which the first non-glucose driven background current is subtracted from the second current is at least two hours and up to sixty-four hours. 
     
     
         6 . The apparatus of  claim 1 , wherein the instructions, when executed, cause the processor to:
 model a second non-glucose driven background current associated with the second sensor over a second time duration that extends past the first time duration;   continue to obtain the second current from the second sensor over the second time duration;   subtract the second non-glucose driven background current from the second current measured over the second time duration to obtain the subtracted second current for the second sensor; and   convert the subtracted second current to the second analyte value.   
     
     
         7 . The apparatus of  claim 6 , wherein the second time duration in which the second non-glucose driven background current is subtracted from the second current is at least 15 days and as long as 32 days. 
     
     
         8 . The apparatus of  claim 6 , wherein the instructions, when executed, cause the processor to model the second non-glucose driven background current based on data retrieved from one or more analyte sensors of a same type as each of the first sensor and the second sensor, previously worn by the subject. 
     
     
         9 . The apparatus of  claim 6 , wherein to obtain the subtracted second current and convert the subtracted second current to the second analyte value, the instructions, when executed, cause the processor to:
 recall one or more previously learned analyte sensitivity values from prior use by the subject of other analyte sensors; and   apply a correction procedure to obtain an accurate analyte sensitivity for the second sensor.   
     
     
         10 . The apparatus of  claim 6 , wherein:
 the instructions, when executed, cause the processor to generate a conversion operation that includes one or more conversion parameters and which is used to convert the subtracted second current to the second analyte value for each of the first time duration and the second time duration.   
     
     
         11 . The apparatus of  claim 10 , wherein:
 each of the first time duration and the second time duration are variable and terminate responsive to an indication that the conversion operation is accurately converting the subtracted current to the second analyte current during each of the first time duration and the second time duration.   
     
     
         12 . The apparatus of  claim 10 , wherein the one or more conversion parameters for the conversion operation are the same between the first time duration and the second time duration. 
     
     
         13 . The apparatus of  claim 10 , wherein the one or more conversion parameters for the conversion operation are different between the first time duration and the second time duration. 
     
     
         14 . An apparatus for calibrating a biosensor inserted into tissue of a subject, comprising:
 a non-transitory memory storing instructions; and   a processor to execute the instructions to:   while a first sensor is inserted into the tissue of the subject, detect insertion of a second sensor into the tissue;   responsive to the detecting, obtain a first current from the first sensor and a second current from the second sensor, and convert the first current into a first analyte value;   in response to an indication that a condition is met for modeling a first non-glucose driven background current associated with the second sensor, predict the first non-glucose driven background current for the second sensor over a first time duration;   during the first time duration, subtract the first non-glucose driven background current from the second current to obtain a subtracted second current for the second sensor; and   convert the subtracted second current to a second analyte value.   
     
     
         15 . The apparatus of  claim 14 , wherein the processor is to execute the instructions to predict the first non-glucose driven background current based on the second current measured prior to the condition being met, and at least in part on one or more of the first current or the first analyte value obtained prior to the condition being met. 
     
     
         16 . The apparatus of  claim 15 , wherein the processor is to execute the instructions to predict the first non-glucose driven background current based on a previously generated pattern of background current changes learned over time from a plurality of other analyte sensors inserted into the subject at earlier times. 
     
     
         17 . The apparatus of  claim 14 , wherein the processor is to execute the instructions to:
 model a second non-glucose driven background current associated with the second sensor over a second time duration that extends past the first time duration;   continue to obtain the second current from the second sensor over the second time duration;   subtract the second non-glucose driven background current from the second current measured over the second time duration to obtain the subtracted second current for the second sensor; and   convert the subtracted second current to the second analyte value.   
     
     
         18 . The apparatus of  claim 17 , wherein to obtain the subtracted second current and convert the subtracted second current to the second analyte value, the processor is to execute the instructions to:
 recall one or more previously learned analyte sensitivity values from prior use by the subject of other analyte sensors; and   apply a correction procedure to obtain an accurate analyte sensitivity for the second sensor.   
     
     
         19 . The apparatus of  claim 17 , wherein the processor is to execute the instructions to generate a conversion operation that includes one or more conversion parameters and which is used to convert the subtracted second current to the second analyte value for each of the first time duration and the second time duration. 
     
     
         20 . The apparatus of  claim 19 , wherein the first time duration and the second time duration are variable and terminate responsive to an indication that the conversion operation is accurately converting the subtracted current to the second analyte current during each of the first time duration and the second time duration.