US 11,701,037 B2
Method and electronics unit for detecting in-vivo properties of a biosensor
Ulrich Mueller, Mannheim (DE); Herbert Wieder, Mannheim (DE); Alexander Poggenwisch, Mannheim (DE); Uli Delventhal, Mannheim (DE); and Andreas Knoerzer, Stuttgart (DE)
Assigned to Roche Diabetes Care, Inc., Indianapolis, IN (US)
Filed by Roche Diabetes Care, Inc., Indianapolis, IN (US)
Filed on Dec. 20, 2019, as Appl. No. 16/723,390.
Application 16/723,390 is a continuation of application No. PCT/EP2018/067619, filed on Jun. 29, 2018.
Prior Publication US 2020/0178868 A1, Jun. 11, 2020
Int. Cl. A61B 5/1486 (2006.01); A61B 5/1495 (2006.01); A61B 5/145 (2006.01)
CPC A61B 5/14865 (2013.01) [A61B 5/14532 (2013.01); A61B 5/1495 (2013.01); A61B 2560/0228 (2013.01)] 13 Claims
OG exemplary drawing
 
1. A method for detecting in-vivo properties of a biosensor adapted for determining a value of an analyte in a body fluid sample, the biosensor having a working electrode covered by a membrane and an enzyme for providing a reaction with the analyte, the method comprising:
a) providing a sensitivity-to-admittance relation of the biosensor;
b) measuring a raw current in the biosensor;
c) measuring an in-vivo current response indicative of the in-vivo admittance of the biosensor, wherein the in-vivo current response is measured at first and second operating points and a time constant τ is determined by the electrical capacitance C of the working electrode and the electrical resistance RM of the membrane by τ=RM·C, wherein the first operating point is selected below τ and the second operating point is selected above τ;
d) determining an analyte value in a sample of a body fluid by using the raw current and compensating an in-vivo sensitivity drift in the biosensor, wherein the in-vivo sensitivity drift is compensated by using the measured value for the raw current and a corrected value for the sensitivity, whereby the sensitivity is determined by using the sensitivity-to-admittance relation from step a); and
e) monitoring a failsafe operation of the biosensor by using the in-vivo current response measured at the first and second operating points.