Detecting Incomplete Fill of Biosensors

• US 20080033667A1
• Filed: 06/16/2005
• Published: 02/07/2008
• Est. Priority Date: 06/17/2004
• Status: Active Grant

• Current Assignee: Ascensia Diabetes Care Holdings AG (PHC Holdings Corporation)
• Original Assignee: Bayer Healthcare LLC (Bayer AG)
• Inventors: Brown, Daniel, Blaschke, Christina
• Granted Patent: US 7,945,394 B2
• Time in Patent Office: Days
• US Class Current: 702/55
• CPC Class Codes: G01N 27/3274 Corrective measures, e.g. error detection, compensation for temperature or hematocrit, calibration coding of calibration information G01N33/48771

Abstract

A method of detecting incomplete filling of an electrochemical biosensor by collecting a series of electrical current values when a constant electrical potential is applied across the working and counter electrodes during a preliminary burn period. The slope of a line determined by linear regression based on the series of current values is used to determine whether or not the biosensor is incompletely filled. If the line has a positive slope, the biosensor is reported to be under filled. If the slope is not positive, the correlation coefficient of the current values is used as a supplemental test to indicate whether or not the biosensor is incompletely filled.

Claims

1. A method of detecting incomplete filling of electrochemical biosensors having working and counter electrodes, the method comprising the acts of:

(a) applying a constant electrical potential across said working and counter electrodes for a predetermined period of time;

(b) measuring the current passing between said working and counter electrodes;

(c) collecting values of the current measured in act (b) at predetermined times during said predetermined period of time of act (a);

(d) determining by linear regression the slope of a line defined by the values of current collected in act (c); and

(e) reporting as incompletely filled a sensor exhibiting a positive slope of a line as determined in act (d).

2. The method of claim 1 further comprising the acts of:

(f) determining the correlation coefficient of the collected data of act (c);

(g) reporting as an incompletely filled a sensor exhibiting a negative slope of a line as determined in act (d) but in which the correlation coefficient determined in act (f) is less than a predetermined value.

3. The method of claim 2 wherein said predetermined value is from about 0.80 to about 0.95.

4. The method of claim 3 wherein said predetermined value is about 0.95.

5. The method of claim 1 wherein said collected values are obtained during the second half of said predetermined period of act (a).

6. The method of claim 1 wherein said collected values of act (c) are at least 5 in number.

7. The method of claim 6 wherein said collected values are at least 6 in number.

8. The method of claim 1 wherein said predetermined period of time of act (a) is from about 2 to about 10 seconds.

9. The method of claim 8 wherein said predetermined period of time of act (a) is 10 seconds.

10. The method of claim 1 wherein said biosensor measures the glucose concentration of whole blood.