Patent ID: 8702926

Claim:
A control solution for use in testing an electrochemical system for measuring the amount of an analyte in a sample, the control solution comprising: (a) a predetermined amount of said analyte; and (b) a predetermined amount of an internal reference compound, said internal reference compound having a higher oxidation potential than said analyte, said predetermined amount of said internal reference compound being dependent upon said predetermined amount of analyte, the control solution being configured to be distinguished from the sample based on a Differential Index (DI), the predetermined amount of the internal reference compound being such that the control solution has a DI of at least 1.5, the DI being defined as DI=i high volt /i low volt where: i high volt is an electrical current resulting from the application of a first potential sufficient to oxidize said internal reference compound and said analyte, and i low volt is an electrical current resulting from the application of a second potential sufficient to oxidize said analyte and insufficient to oxidize said internal reference compound, the second potential being applied before the first potential during the same period.