Optical glucose detector

• US 6,466,807 B1
• Filed: 07/17/2000
• Issued: 10/15/2002
• Est. Priority Date: 08/12/1997
• Status: Expired due to Term

• Current Assignee: Abbott Laboratories Incorporated
• Original Assignee: Abbott Laboratories Incorporated
• Inventors: Turner, Scott J., Dobson, Peter J.
• Primary Examiner(s): Winakur, Eric F.
• Assistant Examiner(s): KREMER, MATTHEW J
• Application Number:
  US09/485,472
• Time in Patent Office: 820 Days
• Field of Search: 600/309-310, 600/322-326, 600/316, 600/476, 600/473, 356/39-41
• US Class Current: 600/316
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters

Abstract

A device for the in vivo measurement of the concentration of an analyte in an aqueous solution comprises a transmitter for illuminating a body part with light at a plurality of predetermined wavelengths. A detector receives light from such body part and generates input signals representative of the intensity of received light at each of the predetermined wavelengths, and a computer coupled to the detector generates an output signal representative of the analyte concentration in the body part by analysis of the input signals received from the detector. The detector is adapted to generate input signals representative of the intensity of light received at three discrete wavelengths, and a formula is provided for calculating the output signal on the basis thereof.

Claims

1. A device for measuring concentration of an analyte in blood comprising a transmitter for illuminating a body part with light at a plurality of predetermined wavelengths;

a detector for receiving light from said body part and generating input signals representative of the intensity of the received light at each said wavelength; and

a computer coupled to the detector for generating an output signal representative of the concentration of the analyte in the blood in said body part by analysis of input signals received from the detector, wherein the output signal S_o is generated from the following formula;

$S_o=\log <br><br>\frac{I_B}{I_A}-\frac{I_C}{I_A}$

where I_A is representative of the intensity of received light at wavelength A at which the transmissivity of the blood is unaltered by the analyte;

I_B is representative of the intensity of received light at wavelength B at which the transmissivity of the blood is increased by the analyte;

I_C is representative of the intensity of received light at wavelength C at which the transmissivity of the blood is reduced by the analyte; and

C>

B>

A.

2. A device according to claim 1 wherein the detector is adapted to generate input signals representative of the intensity of light received at three discrete wavelengths.

3. A device according to claim 1 wherein the analyte is glucose, and wherein A is 810 nm

B is 970 nm

and C is 1053 nm.

4. A device according to claim 1 wherein the transmitter and detector are mounted in a housing for disposition on either side of body part such that the detector receives light from the transmitter after passage through the body part.

5. A device according to claim 1 wherein the transmitter and detector are mounted in a housing for disposition against adjacent sections of tissue on body part such that the detector receives light from the transmitter after diffuse reflection within the body part.

6. A device according to claim 5 including a force transducer for gauging compliance of tissue against which the body part is disposed.

7. A device according to claim 1 wherein the transmitter comprises a source of white light, and the detector comprises photo-diodes for separately monitoring receipt of light at the predetermined wavelengths.

8. A device according to claim 1 wherein the transmitter comprises a plurality of light sources respectively for generating light at the predetermined wavelengths;

and a photo-diode for monitoring the receipt of such light.

9. A device according to claim 1 wherein light from the transmitter is delivered along at least one optical fibre.

10. A device according to claim 1 wherein light is delivered to the detector along at least one optical fibre.

11. A device according to claim 1 wherein light from the transmitter is delivered along at least one optical fibre and light is delivered to the detector along at least one optical fibre, further including a contact section having a surface for engaging a body part, the optical fibres from and to the transmitter and detector terminating at said surface.

12. A method of measuring concentration of an analyte in blood comprising a illuminating a body part with light at a plurality of predetermined wavelengths;

monitoring light at said wavelengths received from the body part and generating input signals representative of the intensity thereof; and

generating an output signal representation of the concentration of the analyte in the blood in said body part by analysis of input signals, wherein the output signal S_o is generated from the following formula;

$S_o=\log <br><br>\frac{I_B}{I_A}-\frac{I_C}{I_A}$

where I_A is representative of the intensity of received light at wavelength A at which the transmissivity of the blood is unaltered by the analyte;

I_B is representative of the intensity of received light at wavelength B at which the transmissivity of the blood is increased by the analyte;

I_C is representative of the intensity of received light at wavelength C at which the transmissivity of the blood is reduced by the analyte; and

C>

B>

A.

13. A method according to claim 12 wherein the detector generates input signals representative of light received at three discrete wavelengths.

14. A method according to claim 12 wherein the analyte is glucose, and wherein A is 810 nm

B is 970 nm

C is 1053 nm.

15. A method according to claim 12 wherein the light received by the detector has passed through said body part.

16. A method according to claim 12 wherein the light received by the detector is generated by diffuse reflection in said body part.