Method of reducing the effect of direct interference current in an electrochemical test strip

Abstract

This invention describes a method of reducing the effect of interfering compounds in a bodily fluid when measuring an analyte using an electrochemical sensor. In particular, the present method is applicable to electrochemical sensors where the sensor includes a substrate, first and second working electrodes, and a reference electrode and either the first and second or only the second working electrode include regions which are bare of reagent. In this invention, an algorithm is described with mathematically corrects for the interference effect using the test strip embodiments of the present invention.

Description

PRIORITY [0001] The present invention claims priority to the following US Provisional Applications: U.S. Provisional Application Ser. No. 60 / 516,252 filed on Oct. 31, 2003; U.S. Provisional Application Ser. No. 60 / 558,424 filed on Mar. 31, 2004; and U.S. Provisional Application Ser. No. 60 / 558,728 filed on Mar. 31, 2004. Which applications are hereby incorporated herein by reference. RELATED APPLICATIONS [0002] The present invention is related to the following co-pending US Applications: U.S. patent application Ser. No. ______ [Attorney Docket Number DDI-5027 USNP], filed on Oct. 29, 2004; U.S. patent application Ser. No. ______ [Attorney Docket Number DDI-5042 USNP], filed on Oct. 29, 2004; U.S. patent application Ser. No. ______ [Attorney Docket Number DDI-5064], filed on Oct. 29, 2004; U.S. patent application Ser. No. ______ [Attorney Docket Number DDI-5066], filed on Oct. 29, 2004; and U.S. patent application Ser. No. ______ [Attorney Docket Number DDI-5067], filed on Oct. 29, 2...

AI Technical Summary

Benefits of technology

[0066] One advantage of the present invention is the ability to use the first and second working electrode to determine that the sample receiving chamber has been sufficiently filled with liquid. It is an advantage of this invention in that the second working electrode not only corrects the interferent effect, but can also measure glucose. This allows for a more accurate results because 2 glucose measurements can be averaged together while using only one test strip.

is the ability to use the first and second working electrode to determine that the sample receiving chamber has been sufficiently filled with liquid. It is an advantage of this invention in that the second working electrode not only corrects the interferent effect, but can also measure glucose. This allows for a more accurate results because 2 glucose measurements can be averaged together while using only one test strip.

Problems solved by technology

In particular, desirable oxidation current results from the interaction of the mediator with the analyte of interest (e.g., glucose) while undesirable oxidation current is generally comprised of interfering compounds being oxidized at the electrode surface and by interaction with the mediator.

However, this technique is not always successful since some interfering compounds such as acetaminophen do not have a net negative charge, and thus, can pass through a negatively charged membrane.

Nor would this technique reduce the oxidation current resulting from the interaction of interfering compounds with some mediators.

However, such selective membranes typically make the test strip more complicated to manufacture and increase the test time because the oxidized glucose must diffuse through the selective membrane to get to the electrode.

A disadvantage of this strategy is that mediators having a relatively low potential are often difficult to synthesize, unstable and have a low water solubility.

A disadvantage of this strategy is that it requires that the test strip include an additional electrode and electrical connection (i.e., the dummy electrode) which cannot be used to measure glucose.

The inclusion of dummy electrode is an inefficient use of an electrode in a glucose measuring system.

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