ELECTRODE LAYOUT FOR BLOOD TEST SENSOR STRIP

• US 20110174637A1
• Filed: 01/19/2010
• Published: 07/21/2011
• Est. Priority Date: 01/19/2010
• Status: Active Grant

• Current Assignee: Embecta Corporation
• Original Assignee: Becton, Dickinson & Co
• Inventors: Schiff, David, Gisler, Scott W., Mondro, Jason
• Granted Patent: US 8,771,202 B2
• Time in Patent Office: Days
• US Class Current: 205/792
• CPC Class Codes: A61B 2562/0295 Strip shaped analyte sensors for apparatus classified in A61B5/145 or A61B5/157
• CPC Class Codes: A61B 2562/046 in a matrix array
• CPC Class Codes: A61B 2562/125 characterised by the manufacture of electrodes
• CPC Class Codes: A61B 5/1411 by percutaneous method, e.g. by lancet
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/1477 non-invasive
• CPC Class Codes: A61B 5/1486 using enzyme electrodes, e.g. with immobilised oxidase
• CPC Class Codes: A61B 5/150022 for capillary blood or interstitial fluid
• CPC Class Codes: A61B 5/150213 Venting means
• CPC Class Codes: A61B 5/150358 Strips for collecting blood, e.g. absorbent optical reagent test strips G01N21/8483; chemical reagent test strips G01N33/4875, G01N33/52
• CPC Class Codes: A61B 5/150412 Pointed piercing elements, e.g. needles, lancets for piercing the skin blade-like piercing elements A61B5/150442
• CPC Class Codes: A61B 5/150503 Single-ended needles hollow piercing element tip design A61B5/150396, needle sets for catheters A61M25/06, needles for bringing media into the body A61M5/32
• CPC Class Codes: A61B 5/1519 comprising driving means, e.g. a spring, for propelling the piercing unit
• CPC Class Codes: A61B 5/157 Devices characterised by integrated means for measuring characteristics of blood
• CPC Class Codes: G01N 27/3271 Amperometric enzyme electrodes for analytes in body fluids, e.g. glucose in blood amperometry per se G01N27/49; aspects concerning the enzyme reagent C12Q1/001
• CPC Class Codes: G01N 27/3272 Test elements therefor, i.e. disposable laminated substrates with electrodes, reagent and channels optical biosensors G01N33/52

Abstract

An improved electrode layout for a continuous strip sensor is provided which reduces misalignment of the electrodes with the contacts which read the position of the strip. Better contact with the electrodes reduces or eliminates transient signals between stop positions of the sensor strip.

Claims

1. An elongated sensor strip for use in a blood sample test device, comprising:

a plurality of test sites arranged in series in a travel direction on the strip, wherein each test site includes a lancet hole, electrodes for determining a blood sample volume, and test electrodes for determining a blood sample characteristic;

each test site comprising

a non conductive substrate layer;

a conductive layer on the substrate layer forming conductive pads defined by non-conductive lines and aligned with device contacts in the blood sample test device and; and

a non-conductive layer superposed on the conductive layer having a window exposing a plurality of the conductive pads.

2. The sensor strip according to claim 1, wherein the conductive pads are formed by depositing a conductive layer and etching lines to form rows and columns of conductive pads.

3. The sensor strip according to claim 1, wherein the conductive pads are arranged in at least three rows corresponding, respectively, to a lancing step position, a blood volume detection step position, and a blood characteristic sensing step position, in a lancing/sensing process.

4. The sensor strip according to claim 3, further comprising a fourth row of conductive pads corresponding to a home position before a lancing/sensing process is commenced.

5. The sensor strip according to claim 1, wherein the conductive pads are arranged into at least four columns corresponding to device contacts in the test device.

6. The sensor strip according to claim 1, wherein the strip is provided with a pressure sensor to determine sufficient pressure on the strip prior to conducting a lancing operation

7. The sensor strip according to claim 1, wherein conductive traces running perpendicular to the travel direction of the strip are covered by a non-conductive cover layer, so that the horizontal traces cannot be contacted by the test device contacts.

8. The sensor strip according to claim 1, wherein each conductive pad has a leading edge in a travel direction of the strip, and the leading edge of at least a first conductive pad in a row is in front of a second conductive pad in the row, so that a signal is obtained from the first conductive pad before a signal is obtained from the second conductive pad.

9. The sensor strip according to claim 1, wherein the conductive layer is sputtered metal.

10. The sensor strip according to claim 1, wherein the test electrodes for determining a blood sample characteristic are located in a pair of reagent wells and adapted to perform a blood glucose measurement.

11. The sensor strip according to claim 1, wherein the conductive pads each have a surface area in a range of 1.0 mm² to about 3.0 mm².

12. A blood sample acquisition and sensing system, comprising:

device contacts;

an elongated strip having a plurality of test sites arranged in series in a travel direction on the strip, wherein each test site includes a lancet hole, electrodes for determining a blood sample volume, test electrodes for determining a blood sample characteristic, and columns of conductive pads aligned with the device contacts for making electrical contact between the strip and the device contacts;

a lancet and lancet injector;

a motor adapted to advance the strip; and

a processor adapted to receive signals produced when the device contacts make electrical contact with the conductive pads on the strip and adapted to communicate with the lancet injector to perform a lancing operation, the motor to perform a strip advance operation, and the test electrodes to perform a blood sample characteristic measurement operation.

13. The system according to claim 12, wherein the conductive pads on the strip are arranged in at least three rows corresponding, respectively, to a lancing step position, a blood volume detection step position, and a blood characteristic sensing step position, in a lancing/sensing process.

14. The system according to claim 13, further comprising a fourth row of conductive pads corresponding to a home position before a lancing/sensing process is commenced.

15. The system according to claim 12, wherein the conductive pads are arranged into at least four columns corresponding to the device contacts in the test device.

16. The system according to claim 12, further comprising a pressure sensor on the strip communicating with the processor to signal sufficient pressure to initiate the lancing/sensing process.

17. The system according to claim 12, wherein a non-conductive layer covers horizontal traces connecting conductive pads to the electrodes and prevents the device contacts from directly contacting the horizontal traces.

18. The system according to claim 13, wherein a leading edge in the travel direction of a first conductive pad in a row is in front of a leading edge of a second conductive pad in the row, so that a signal produced by electrical contact between a device contact and the first conductive pad is received before a signal produced by electrical contact between a device contact and the second conductive pad.

19. The system according to claim 12, wherein the device contacts, strip, lancet, motor and processor are positioned in a unitary housing

20. The system according to claim 18, wherein the housing includes user-operable controls and a display.

21. A method for performing a plurality of blood sample acquisition and testing procedures on a strip, comprising the steps of:

providing an elongated strip having a plurality of test sites arranged in series in a travel direction on the strip, wherein each test site includes a lancet hole, electrodes for determining a blood sample volume, test electrodes for determining a blood sample characteristic, and conductive pads for making electrical contact with a blood test sensor device;

injecting a lancet through the lancet hole at a first test site into a subject to obtain a blood sample contacting the strip;

contacting the blood sample with the electrodes for determining a blood sample volume to produce a signal when a blood sample volume is detected;

advancing the strip responsive to the signal produced when a blood sample is detected;

contacting the blood sample with the test electrodes to obtain a blood sample characteristic signal; and

advancing the strip to a second test site.

22. The method according to claim 21, comprising

at least three separate rows of conductive pads corresponding to at least a lancing step position, a blood volume detection step position, and a blood characteristic sensing step position of the strip in a lancing/sensing process;

at least four columns of conductive pads aligned with respective device contacts; and

wherein

at least two of the conductive pads in each said row are grounded at each of said positions in the lancing/sensing process.

23. The method according to claim 22, further comprising

a fourth row of conductive pads, producing a signal corresponding to a home position when electrical contact is made with conductive pads in the fourth row.

24. The method according to claim 21, further comprising the step of detecting the pressure of the strip against a subject prior to injecting the lancet into the subject.

25. The method according to claim 21, comprising the step of obtaining a blood sample volume signal when a blood droplet bridges a pair of electrodes for determining a blood sample volume to create an electrical short between the electrodes.

26. The method according to claim 21, wherein the blood sample characteristic measurement is an electrochemical measurement of blood glucose obtained by passing current through the blood sample.

27. The method according to claim 21, comprising the step of protecting horizontal traces connecting conductive pads to the electrodes and preventing the device contacts from directly contacting the horizontal traces by providing a non-conductive cover layer having a window.