BLOOD GLUCOSE SENSOR

• US 20110015546A1
• Filed: 07/14/2009
• Published: 01/20/2011
• Est. Priority Date: 07/14/2009
• Status: Active Grant

• Current Assignee: Embecta Corporation
• Original Assignee: Becton, Dickinson & Co
• Inventors: Schiff, David R., Albert, Jonathan D., Mondro, Jason
• Granted Patent: US 8,337,423 B2
• Time in Patent Office: Days
• US Class Current: 600/583
• CPC Class Codes: A61B 2562/0295 Strip shaped analyte sensors for apparatus classified in A61B5/145 or A61B5/157 disposable multilayered or laminated electrodes G01N27/307; details of handling chemical test elements G01N33/4875
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• 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 5/150358 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 33/48764 Test tape taken off a spool

Abstract

The invention is directed to an apparatus and method for blood sample acquisition and testing. The apparatus incorporates a test strip having a blood sample volume detection area in which a blood sample is accumulated and a minimum blood sample volume is detected. Once a minimum blood sample volume is detected, the test strip is moved with respect to the blood sample extraction site so that a bending surface of the test strip is presented to the blood sample, utilizing the surface tension of the blood sample droplet to facilitate movement of the blood sample to a measurement site on the strip where blood glucose in the sample is measured.

Claims

1. A blood glucose sensor for measuring blood glucose in a blood sample withdrawn from a blood sample extraction site on a subject'"'"'s body, comprising:

a test strip;

conductive contacts positioned on the test strip and defining a blood sample volume detection area;

said test strip having a blood transport channel having a mouth at one end in fluid communication with the blood sample volume detection area; and

a measurement site at an opposite end of the blood transport channel;

the test strip being movable in a bending state between a first position in which the blood sample volume detection area is opposite the blood sample extraction site and a second position in which the mouth of the blood transport channel is opposite the blood sample extraction site,

wherein a blood sample bridging the contacts defining the blood sample volume detection area permits electrical communication between the contacts to detect a blood sample volume; and

wherein the detected blood sample volume is sufficiently large that the blood sample moves through the blood transport channel to contact the measurement site when the mouth of the blood transport channel is moved to said blood sample extraction site.

2. The blood glucose sensor of claim 1, further comprising a bending surface supporting the test strip in a bending state opposite the blood sample extraction site.

3. The blood glucose sensor of claim 2, wherein the bending surface is a roller and the test strip is movable over the roller between a first position in which the blood volume detection area is opposite the extraction site in a bending state and a second position in which blood is directed through the blood transport channel to the measurement site while the blood transport channel is in a bending state.

4. The blood glucose sensor of claim 3, wherein the test strip arranged on the roller is continuous, having a plurality of functional areas, each functional area on the test strip comprising a volume detection area, blood transport channel and measurement site, and each functional area is separated by a neutral portion, the functional areas being arranged on the test strip for successive blood glucose measurements.

5. The blood glucose sensor of claim 4, further comprising a housing and a lancet arranged in the housing to pass through the test strip at the blood volume detection area and to withdraw a blood sample from a subcutaneous space in a subject'"'"'s body beneath the blood sample extraction site.

6. The blood glucose sensor of claim 5, further comprising a first seal isolating the functional areas of the test strip that have been used for blood glucose measurement from an environment outside of the housing, and a second seal isolating the unused areas of test strip from the environment.

7. The blood glucose sensor of claim 1, further comprising a cartridge containing a plurality of test strips, and a guide member maintaining individual test strips in a bending state opposite a blood sample extraction site on a patient'"'"'s body.

8. The blood glucose sensor of claim 1, wherein the blood sample volume detection area is sized so that a blood sample having a volume of about 0.2 μ

L to about 1.0 μ

L causes the blood sample to contact the conductive contacts in the blood sample volume detection area to generate a signal indicating that a minimum blood sample volume has been obtained.

9. The blood glucose sensor of claim 1, wherein a bending portion of the test strip contacts a blood sample on the blood sample extraction site so that surface tension of the blood sample in combination with the movement of the test strip pulls the blood sample in a direction from the blood sample volume detection area to the mouth of the blood transport channel.

10. The blood glucose sensor of claim 1, comprising an optical sensor for measuring blood glucose in the blood sample at the measurement site.

11. The blood glucose sensor of claim 1, comprising an electrochemical sensor for measuring blood glucose in the blood sample at the measurement site.

12. The blood glucose sensor of claim 2, comprising a plurality of test strips in a circular configuration on a disc or drum.

13. A blood glucose sensor, comprising:

a unitary housing containing

means for forming a blood sample extraction site on a patient'"'"'s body;

means for removing a blood sample from a subcutaneous space beneath the blood sample extraction site;

a substantially planar test strip;

means for maintaining a portion of the test strip in a bending state opposite the blood sample extraction site.

a volume detection area positioned on the test strip, the volume detection area having means for detecting a volume of the blood sample and producing a signal when a minimum blood sample volume is present;

means for advancing the test strip in response to the signal produced when a minimum blood sample volume is present;

means for transporting the blood sample from the volume detection area to a measurement site;

means for obtaining a blood glucose measurement of the blood sample at the measurement site to produce a measurement signal;

means for advancing the test strip in response to the measurement signal.

14. A method for measuring blood glucose, comprising the steps of:

positioning a test strip having a bending portion in a first position over a blood sample extraction site on a subject'"'"'s body, so that the bending portion of the test strip is opposite the blood sample extraction site;

passing a lancet through the test strip and into a subcutaneous space in the subject'"'"'s body beneath the sample extraction site and extracting a blood sample;

accumulating blood in a blood sample volume detection area defined by conductive contacts on the test strip;

contacting the conductive contacts with the blood sample to generate a signal when a minimum blood sample volume is detected;

moving the blood sample through a blood transport channel to a blood glucose measurement site while maintaining the blood transport channel in a bending state;

measuring blood glucose in the blood sample at the measurement site.

15. The method of claim 14, wherein the test strip is continuous and mounted on a roller maintaining the test strip in a bent state opposite the blood sample extraction site, so that blood glucose measurements can be made on successive functional areas on the test strip, and comprising the further step of

advancing the continuous test strip from a first position in response to the signal generated when a minimum blood sample volume is detected to a second position when the blood glucose measurement is made.

16. The method of claim 15, wherein the test strip is positioned within a housing and comprising the further step of

advancing the test strip from the second position when the measurement is made to a third position in which the functional areas of the test strip are not exposed to an environment outside of the housing.

17. The method of claim 14, comprising the further step of

supplying an individual test strip from a cartridge containing a plurality of test strips and maintaining the bending portion of the test strip opposite the blood sample extraction site with a guide.

18. The method of claim 14, wherein the step of measuring the blood glucose is performed with an electrochemical sensor.

19. The method of claim 14, wherein the step of measuring the blood glucose is performed with an optical sensor.

20. The method of claim 14, wherein the minimum blood sample volume is in a range of about 0.2 μ

L to about 1.0 μ

L.