ANALYTE METER AND METHOD OF OPERATION

• US 20140299483A1
• Filed: 04/05/2013
• Published: 10/09/2014
• Est. Priority Date: 04/05/2013
• Status: Abandoned Application

• Current Assignee: LifeScan Scotland Limited (Johnson & Johnson)
• Original Assignee: LifeScan Scotland Limited (Johnson & Johnson)
• Inventors: McColl, David, Smith, Antony, Guthrie, Brian, Elder, David, Lloyd, Tim, Massari, Rossano, Forlani, Christian
• Application Number:
  US13/857,280
• Publication Number:
  US 20140299483A1
• Time in Patent Office: Days
• US Class Current: 205/782
• CPC Class Codes: G01N 27/3273 Devices therefor, e.g. test element readers, circuitry details not specific to biochemical electrodes G01N33/4875
• CPC Class Codes: G01N 27/3274 Corrective measures, e.g. error detection, compensation for temperature or hematocrit, calibration coding of calibration information G01N33/48771
• CPC Class Codes: G01N 27/3275 Sensing specific biomolecules, e.g. nucleic acid strands, based on an electrode surface reaction

Abstract

An analyte meter having a test strip port is configured to transmit an electric signal through a received test strip with a sample. A pair of electrodes apply the electric signal and receive an electrical response from the test strip. A processing unit analyzes the electrical response and uses the response to determine an analyte level of the sample.

Claims

1. An analyte meter comprising:

an analyte port for receiving a test strip, the test strip comprising electrodes and the analyte port comprising contacts for electrically contacting the electrodes of the test strip, the test strip further comprising a chamber for receiving a blood sample from a user'"'"'s finger touching the test strip;

an electric circuit connected to the contacts, wherein the electric circuit is configured to generate a sinusoidal electric signal, to transmit the sinusoidal electric signal through the test strip and through the sample via the contacts, to receive a sinusoidal electric response from the test strip generated by the sinusoidal electric signal, and wherein the electric circuit comprises means for minimizing effects on the sinusoidal electric response caused by the user'"'"'s finger touching the test strip; and

a processing unit connected to the electric circuit, the processing unit configured to receive the sinusoidal electrical response from the test strip, the sinusoidal electrical response comprising a measurable magnitude that is representative of a first analyte level of the blood sample, and wherein the processing unit is configured to determine a second analyte level of the blood sample based on the measured magnitude of the sinusoidal electrical response.

2. The analyte meter of claim 1, wherein the sinusoidal electrical response comprises a magnitude different from a magnitude of the sinusoidal electric signal.

3. The analyte meter of claim 2, wherein the sinusoidal electrical signal comprises a frequency between about 50 kHz and about 100 kHz.

4. The analyte meter of claim 2, wherein the sinusoidal electrical signal comprises a frequency between about 70 kHz and about 80 kHz.

5. The analyte meter of claim 2, wherein the sinusoidal electrical signal comprises a frequency at about 77 kHz.

6. The analyte meter of claim 1, wherein the first analyte level of the sample is a hematocrit level, and the second analyte level of the sample is a glucose level.

7. The analyte meter of claim 1, further comprising:

a square wave generator controlled by the processing unit, the square wave generator configured to generate an electric signal at a frequency of the sinusoidal electric signal; and

a demodulation circuit electrically connected to the processing unit and to the electric circuit, the demodulation circuit receiving the sinusoidal electrical response to decompose it into real and imaginary components, and to transmit the real and imaginary components to the processing unit.

8. A method of operating an analyte meter, the method comprising:

detecting insertion of a test strip into the analyte meter;

providing a sample onto the test strip based upon finger contact therewith;

driving a known electric input signal through the test strip, the known electric input signal having a frequency between about 50 kHz to about 100 kHz;

measuring magnitude and phase characteristics of an electric output signal received from the test strip in response to the electric input signal; and

determining an analyte level of the sample based on the magnitude of the electric output signal in order to minimize finger contact influence on the analyte level results.

9. The method of claim 8, wherein the signal driving step comprises driving a sinusoidal electric input signal having a known amplitude and frequency.

10. The method of claim 8, wherein the signal driving step comprises driving a sinusoidal electric input signal having a frequency of between about 70 kHz and about 80 kHz.

11. The method of claim 8, wherein the signal driving step comprises driving a sinusoidal electric input signal having a frequency of about 77 kHz.

12. The method of claim 8, wherein the signal driving step comprises generating a square wave signal using a square wave generator and converting the square wave signal into a sinusoidal signal using a filter.

13. The method of claim 12, wherein the magnitude and phase measuring step comprises decomposing the electric output signal into real and imaginary components using a demodulation circuit.

14. A simulation circuit comprising:

a first circuit portion configured to simulate electrical characteristics of a test strip inserted in an analyte meter, the test strip having a sample thereon; and

a second circuit portion connected to the first circuit portion, the second circuit portion configured to simulate electrical characteristics of a finger of a user in contact with the test strip.

15. The simulation circuit of claim 14, further comprising a third circuit portion connected to the second circuit portion, the third circuit portion configured to simulate an electrically grounded body of the user.

16. The simulation circuit of claim 14, wherein the first circuit portion comprises two electrical terminals having a strip port capacitor connected therebetween to simulate electrical characteristics of a strip port connector of the analyte meter.

17. The simulation circuit of claim 14, wherein the first circuit portion further comprises two test strip resistors each connected to a different one of the electrical terminals in parallel with the strip port capacitor, and a test strip capacitor connected between the two test strip resistors, to simulate electrical characteristics of the test strip.

18. The simulation circuit of claim 17, wherein the first circuit portion further comprises a sample resistor connected in parallel with the test strip capacitor to a first one of the test strip resistors and to one terminal of a sample capacitor, the other terminal of the sample capacitor connected to a second one of the test strip resistors, the sample resistor and the sample capacitor for simulating electrical characteristics of the test strip having a sample thereon.

19. The simulation circuit of claim 18, wherein the second circuit portion comprises:

a finger resistor and a first finger capacitor connected in parallel to a node of the first circuit portion, the node of the first circuit portion connected in parallel to the first one of the test strip resistors, the strip capacitor, and the sample resistor; and

a second finger capacitor connected in parallel to the finger resistor and the first finger capacitor opposite the node of the first circuit.

20. The simulation circuit of claim 19, further comprising a third circuit portion connected to the second circuit portion, the third circuit portion configured to simulate an electrically grounded body of the user.

21. The simulation circuit of claim 20, wherein the third circuit portion comprises a body resistor connected in series with a body capacitor between the second circuit portion and ground.

22. The simulation circuit of claim 21, wherein the strip port capacitor, the test strip capacitor, and the two test strip resistors each comprise preselected fixed sizes for simulating the test strip inserted in the analyte meter.

23. The simulation circuit of claim 22, wherein the finger resistor, the first and second finger capacitors, the body resistor, and the body capacitor each comprise variable sizes configured to simulate operation of the analyte meter during an assay.

24. A method of manufacturing an analyte meter capable of effectively minimizing the influence of finger contact electrically on a test strip used in conjunction with the test meter, the method comprising:

disposing a square wave generator in a housing of the meter to generate a square wave signal having a frequency between about 50 kHz and about 100 kHz;

connecting a first low pass filter circuit to the square wave generator for converting the square wave signal to a sinusoidal signal;

connecting electrodes to the first low pass filter for driving the sinusoidal signal through a test strip brought into electrical contact with the electrodes;

connecting a demodulation circuit and a second low pass filter circuit to the electrodes for receiving an electrical output from the test strip and for decomposing the electrical output, the electrical output generated in the test strip in response to the sinusoidal signal;

connecting a processing unit to the second low pass filter circuit; and

programming the processing unit to calculate a magnitude of the decomposed electrical output.

25. The method of manufacturing of claim 24, further comprising programming the processing unit to calculate an analyte level of a sample in the test strip based on the calculated magnitude of the decomposed electrical output.

26. The method of manufacturing of claim 24, wherein the square wave generator generates a square wave signal having a frequency between about 70 kHz and about 80 kHz.

27. The method of manufacturing of claim 24, wherein the square wave generator generates a square wave signal having a frequency at about 77 kHz.

28. A portable analyte test meter for use with an associated analytical test strip in the determination of a hematocrit concentration of a blood sample applied to the test strip through finger contact, said test meter comprising:

a housing;

a port for receiving the associated analytical test strip;

a low pass filter circuit block disposed in the housing;

a square wave generator circuit block disposed in the housing and connected to the low pass filter circuit block, the square wave generator configured to generate a square wave at a frequency in the range of about 70 kHz to about 80 kHz and to transmit the generated square wave signal to the associated analytical test strip in the port via the low pass filter circuit block; and

a processing block configured to calculate a magnitude of a signal received from the associated analytical test strip, wherein the signal received from the associated analytical test strip originated from the generated square wave.

29. The portable analyte test meter of claim 28, wherein the port comprises electrodes for electrically connecting to the associated analytical test strip.

30. The portable analyte test meter of claim 29, wherein the magnitude of the signal received from the associated analytical test strip indicates the hematocrit concentration and wherein the processing block calculates the hematocrit concentration based on the magnitude of the signal.

31. The portable analyte test meter of claim 28, wherein the associated analytical test strip comprises a chamber having a sample therein.

32. The portable analyte test meter of claim 28, wherein the low pass filter block is configured to transform the square wave signal into a sinusoidal signal.

33. A method for employing a portable analyte test meter with an analytical test strip onto which a blood sample is applied using finger contact therewith, said method comprising:

receiving said analytical test strip into a port of said portable analyte test meter;

generating a square wave at a frequency in the range of about 70 kHz to about 80 kHz using a square wave generator circuit block;

transmitting the generated square wave signal to said inserted analytical test strip via a low pass filter;

measuring the magnitude of a signal generated from the analytical test strip at said generated frequency so as to minimize the electrical effects of excess finger contact with said strip; and

determining an analyte concentration of the blood sample applied to the analytical test strip based on the measured magnitude.

34. The method of claim 33, wherein the transmitting step comprises converting the generated square wave signal into a sinusoidal signal.

35. The method of claim 34, wherein the receiving step comprises connecting electrodes of the test meter to the analytical test strip.

36. The method of claim 35, wherein the transmitting step comprises transmitting the sinusoidal signal into the blood sample.