Optical component based temperature measurement in analyte detection devices

• US 6,753,187 B2
• Filed: 05/09/2001
• Issued: 06/22/2004
• Est. Priority Date: 05/09/2001
• Status: Expired due to Term

• Current Assignee: Cilag Gmbh International (Johnson & Johnson)
• Original Assignee: Lifescan Incorporated (Duv Holding Corporation)
• Inventors: Yung, Anthony, Cizdziel, Phillip, Sohrab, Borzu
• Primary Examiner(s): ALEXANDER, LYLE
• Application Number:
  US09/851,753
• Publication Number:
  US 20020168776A1
• Time in Patent Office: 1,140 Days
• Field of Search: 422/56, 422/58, 422/61, 422/82.05, 422/82.06, 422/82.12, 936/164, 936/169
• US Class Current: 436/169
• CPC Class Codes: G01N 21/8483 Investigating reagent band test-element handling not specific to a test method G01N33/4875; analytical elements specific to chemical analysis of biological material G01N33/52; autometer with reagent band G01N35/04
• CPC Class Codes: Y10T 436/144444 Glucose

Abstract

Reflectance based methods and devices are provided for determining the concentration of an analyte in a fluid sample. In practicing the subject methods, a fluid sample is applied to a matrix impregnated with a signal producing system. The signal producing system produces a detectable product in an amount proportional to the amount of analyte in the sample. A surface of the matrix is then illuminated and a reflectance measurement is obtained therefrom, generally following a predetermined incubation period. An optical component, preferably the illumination or light detection means, is also employed to obtain a temperature value corresponding to the ambient temperature of the matrix. The analyte concentration of the sample is then obtained from the reflectance measurement using an algorithm that employs the optical component derived temperature value. The subject methods and devices are suited for use in the detection of a variety of different types of fluid analytes, and are particularly suited for use in detecting the concentration of glucose in whole blood.

Claims

1. A method for determining the concentration of an analyte in a sample of fluid, said method comprising:

contacting said sample with a matrix comprising a signal producing system that produces a colored product on said matrix in an amount proportional to the amount of analyte in said sample;

illuminating a surface of said matrix with an illumination means;

collecting light from said surface with a light detection means to obtain an optical measurement;

obtaining an ambient temperature value proximal said matrix using said light detection means; and

determining said analyte concentration in said sample from said optical measurement using an algorithm that employs said ambient temperature value.

2. The method according to claim 1, wherein said collecting comprises collecting reflected light and said optical measurement is a reflectance measurement.

3. The method according to claim 2, wherein said ambient temperature value is obtained at least once at a time prior to, during and/or after obtainment of said reflectance measurement.

4. The method according to claim 1, wherein said illumination means is a light emitting diode.

5. The method according to claim 1, wherein said light detection means is a temperature sensitive light detector.

6. The method according to claim 1, wherein said fluid is a body fluid.

7. The method according to claim 6, wherein said body fluid is whole blood or a fraction thereof.

8. The method according to claim 6, wherein said analyte is glucose.

9. The method according to claim 1, wherein said matrix is a component of a reagent test strip.

10. The method according to claim 9, wherein said contacting comprises applying said sample to a sample application area of said matrix.

11. The method according to claim 10, wherein said surface of said matrix that is illuminated by said illumination means is a surface of said matrix located opposite said sample application area.

12. The method according to claim 1, wherein said collecting step (c) occurs after a predetermined incubation period.

13. The method according to claim 12, wherein said temperature value is obtained during said predetermined incubation period.

14. A method for determining the concentration of a blood analyte in a blood sample, said method comprising:

contacting said blood sample with a first surface of a matrix impregnated with a signal producing system that produces a colored product on a second surface opposite said first surface in an amount proportional to the amount of analyte in said blood sample;

illuminating said second surface of said matrix with at least one light emitting diode;

collecting light reflected from said second surface with a photodetector following a predetermined incubation period to obtain a reflectance measurement;

obtaining at least one ambient temperature value proximal said matrix using said photodetector during said incubation period; and

determining said analyte concentration in said blood sample from said reflectance measurement using an algorithm that employs said ambient temperature value.

15. The method according to claim 14, wherein said analyte is glucose.

16. The method according to claim 15, wherein said blood sample is whole blood.

17. An apparatus for measuring a concentration of an analyte in a fluid sample, said apparatus comprising:

a chamber for removably accepting a reagent test strip that includes a porous matrix pad which (i) has a first surface for accepting the sample and a reflective second surface opposite to the first surface, (ii) allows the sample to travel through the pad from the first surface toward the second surface, and (iii) is impregnated with one or more reagents of a signal producing system that reacts with said analyte to cause a change in the reflectance of the second surface;

illumination means for illuminating the second surface of the pad;

light detection means for monitoring intensity of light reflected from the second surface of the pad;

ambient temperature means for obtaining an ambient temperature value proximal said porous matrix pad, wherein said ambient temperature means is said light detection means; and

means for calculating the analyte concentration from the intensity of reflected light, wherein said means comprises an algorithm that employs said ambient temperature value, wherein said algorithm is recorded on a computer readable medium component of said apparatus.

18. The apparatus according to claim 17, wherein said apparatus further comprises a means for initiating a predetermined time interval upon measuring a change in intensity of reflected light that is indicative of the arrival of a portion of the sample at the second surface.

19. The apparatus according to claim 17, wherein said illumination means is a light emitting diode.

20. The apparatus according to claim 17, wherein said signal producing system produces a detectable product that is proportional to the amount of glucose in the blood sample.