Disposable electronic diagnostic instrument

• US 5,795,543 A
• Filed: 07/21/1997
• Issued: 08/18/1998
• Est. Priority Date: 11/14/1994
• Status: Expired due to Term

• Current Assignee: Advanced Care Products, Ltd.
• Original Assignee: Advanced Care Products, Ltd.
• Inventors: Delahanty, Francis T., Strahs, Kenneth R., Moorman, Michael, Conner, Timothy J., Poto, Edward M., Wieck, Henry
• Primary Examiner(s): Pyon, Harold Y.
• Application Number:
  US08/897,490
• Time in Patent Office: 393 Days
• Field of Search: 422/55-58, 422/61, 422/68.1, 422/82.05, 436/46, 436/63, 436/95, 436/166, 436/169, 435/14, 435/805, 435/808, 435/810
• US Class Current: 422/82.05
• CPC Class Codes: G01N 21/47 Scattering, i.e. diffuse reflection G01N21/25, G01N21/41 take precedence G01N21/55 takes precedence
• 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: G01N 33/92 involving lipids, e.g. cholesterol , lipoproteins, or their receptors steroid hormones G01N33/743
• CPC Class Codes: Y10S 435/805 Test papers
• CPC Class Codes: Y10S 435/808 Optical sensing apparatus
• CPC Class Codes: Y10S 435/81 Packaged device or kit
• CPC Class Codes: Y10T 436/112499 with sample on test slide
• CPC Class Codes: Y10T 436/144444 Glucose

Abstract

The invention relates to a disposable electronic diagnostic instrument designed for use in an Over-the-Counter (OTC) cholesterol test kit for measuring cholesterol levels of blood. The instrument is designed and calibrated specifically for use with diagnostic test strips supplied with the OTC cholesterol test kit.

Claims

1. A disposable diagnostic instrument calibrated for use with a test strip to which a blood sample is applied, comprising:

a. an instrument housing having keying guides defining a location as which said strip is placed, and defining a test reading aperture on said strip on which one or more drops of blood to be tested are inoculated, said test reading aperture defining a test area;

b. a sensor switch located adjacent said keying guide and contacted by the strip in response to the strip being inserted into the guide, and a control circuit, the switch connected to the control circuit for activation of the instrument by providing power to the instrument in order to operate the instrument

c. a light source positioned to emit radiation of desired wavelengths towards said test area and a photodetector positioned to detect radiation reflected by said test areas said light source and photodetector capable of analyzing said blood sample at said desired wavelengths to determine the amount of cholesterol in said blood sample;

d. a display mounted on said instrument housing for displaying instrumental prompt icons and cholesterol level readings;

e. a first control circuit, said first control circuit capable of performing self-diagnostic testing of said instrument to determine the capability of said photodetector to read said light source within a desired range;

f. a second control circuit, said second control circuit controlling the operation of said light source, analyzing the output signal of said photodetector, and controlling the operation of said display;

wherein said instrument measures the change in reflectance of said strip in response to a test solution being applied to said strip, and wherein said keying guides include at least one lateral edge guide for engaging a lateral edge of strip and an angled fore guide for engaging an angled fore edge of said strip.

2. The diagnostic instrument according to claim 1, wherein said second control circuit is implemented in an application specific integrated circuit.

3. The diagnostic instrument according to claim 1, wherein said display comprises a liquid crystal display.

4. The diagnostic instrument according to claim 1, wherein said keying guides include at least one lateral edge guide for engaging a lateral edge of said strip and an angled fore guide for engaging an angled fore edge of said strip, said angled fore guide being positioned off-center with respect to said strip, such that said angled fore guide only when said strip is properly positioned in said instrument housing.

5. The diagnostic instrument according to claim 1, wherein said second control circuit causes said liquid crystal display to exhibit a cholesterol level reading.

6. The diagnostic instrument according to claim 1 wherein said second control circuit comprises a memory, and said strip comprises measured reflectance levels, wherein said measured reflectance levels are stored in said memory of said second control circuit.

7. The diagnostic instrument according to claim 6 wherein said second control circuit memory comprises an internal flare value.

8. The diagnostic instrument according to claim 1, wherein said light source comprises a planar surface, said light source is mounted with its longitudinal light emitting axis substantially perpendicular to said planar surface, and said photodetector is mounted spaced from said light emitting diode with its longitudinal light detecting axis substantially perpendicular to said planar surface.

9. The diagnostic instrument according to claim 8, wherein said light source comprises a light emitting diode, and said photodetector comprises a silicon photodiode.

10. The diagnostic instrument according to claim 8, wherein a flare screen extending substantially perpendicular to said planar surface is positioned between said light emitting diode and said photodetector.

11. The diagnostic instrument according to claim 8, including an optical bandpass filter, having bandpass wavelengths matching said desired wavelengths said optical filter mounted over said light source and said photodetector.

12. The diagnostic instrument according to claim 1, wherein insertion of said strip into said instrument activates said first and second control circuits.

13. The diagnostic instrument according to claim 12, wherein said activation of said first control circuit determines optical reflectance levels of said strip.

14. The diagnostic instrument according to claim 1, wherein said second control circuit contains a memory, said memory storing calibration threshold levels.

15. The diagnostic instrument according to claim 14 wherein said calibration threshold levels comprise cholesterol threshold levels of about 100 mg/dl, 200 mg/dl and 240 mg/dl.

16. The diagnostic instrument according to claim 1, wherein insertion of said strip into said instrument activates said first control circuit wherein optical reflectance levels of said strip are determined.

17. The diagnostic instrument according to claim 16, wherein a sensor switch is located adjacent said fore guide for activating said first control circuit in response to said strip being inserted into said instrument.

18. The diagnostic instrument according to claim 17, wherein after said strip is inserted into said instrument, said first control circuit reduces power output of said light source and takes a reading as an internal check of the performance of said circuits.

19. The diagnostic instrument according to claim 1, wherein said second control circuit causes said liquid crystal display to exhibit prompt icons during usage of said instrument, said icons comprising an add blood icon, a timer icon and an error icon.

20. The diagnostic instrument according to claim 19, wherein said cholesterol level reading comprises an under 200 (mg/dl) reading, a 200 to 240 (mg/dl) reading and an over 240 (mg/dl) reading.

21. The diagnostic instrument according to claim 20, wherein said second control circuit causes said liquid crystal display to exhibit prompt icons during usage of said instrument, said icons comprising an add blood icon, a timer icon, and an error icon.

22. The diagnostic instrument according to claim 21, wherein said second control circuit causes said liquid crystal display to exhibit a cholesterol level reading, said cholesterol level reading comprising an under 200 (mg/dl) reading, a 200 to 240 (mg/dl) reading, and an over 240 (mg/dl) reading.

23. The diagnostic instrument according to claim 22, wherein said keying guides include at least one lateral edge guide for engaging a lateral edge of said strip, and an angled fore guide for engaging an angled fore edge of said strip, said angled fore guide being positioned off-center with respect to said strip, such that said angled fore edge of said strip can properly engage said angled fore guide only when said strip is properly positioned in said instrument housing.

24. The instrument according to claim 23, wherein a sensor switch is located adjacent said fore guide for activating said first control circuit in response to said strip being placed in said instrument.

25. The diagnostic instrument according to claim 24, wherein said display comprises a liquid crystal display.

26. The diagnostic instrument according to claim 25, wherein said light source comprises a light emitting diode, and said photodetector comprises a silicon photodiode.

27. The diagnostic instrument according to claim 26, wherein said test area comprises a planar surface, said light emitting diode is mounted with its longitudinal light emitting axis substantially perpendicular to said planar surface, and said photodiode is mounted spaced from said light emitting diode with its longitudinal light detecting axis substantially perpendicular to said planar surface.

28. The diagnostic instrument according to claim 27, wherein a flare screen extending substantially perpendicular to said planar surface is positioned between said light emitting diode and said photodetector.

29. The diagnostic instrument according to claim 28, wherein an optical filter, having bandpass wavelengths matching said desired wavelengths, is mounted over said light emitting diode and said phototdetector.

30. An electronic instrument for use with a chemical test strip with a simplified user interface comprising:

a. an instrument having keying guides defining a location at which a chemical test strip is placed;

b. a sensor switch located adjacent to said keying guides for activating said instrument in response to said strip being inserted into said instrument, wherein said insertion activates said instrument; and

means is provided for testing the performance of said instrument comprising;

c. A control circuit, the switch connected to the control circuit for activation of the instrument by providing power to the instrument in order to operate the instrument;

d. a first strip having a defined reflectance, said strip engaging said sensor switch to activate a first control circuit to measure reflectance of said first strip when inserted into said instrument; and

e. a second strip, insertable into said instrument after removal of said first strip wherein the edges of said second strip do not engage said sensor switch when said second strip is inserted into said instrument, and further comprising two regions of defined reflectance, wherein said first region is used as an indicator to said first control circuit that said strip is being measured, and said second region defining the change in measured reflectance;

wherein said instrument measures the change in reflectance of said strip in response to a test solution being applied to said strip, and wherein said keying guides include at least one lateral edge guide for engaging a lateral edge of strip and an angled fore guide for engaging an angled fore edge of said strip.

31. The electronic instrument according to claim 30 wherein said first and second strips comprise the top side and bottom side of a single strip.