Method and instrument for measuring blood sugar level

• US 6,493,069 B1
• Filed: 10/06/2000
• Issued: 12/10/2002
• Est. Priority Date: 07/24/1998
• Status: Expired due to Term

• Current Assignee: Aisin Seiki Co., Ltd. (Aisin Corp.), Terumo Kabushiki Kaisha (Terumo Corporation)
• Original Assignee: Terumo Kabushiki Kaisha (Terumo Corporation)
• Inventors: Nagashimada, Masaru, Ohyu, Syozo
• Primary Examiner(s): STAFIRA, MICHAEL PATRICK
• Application Number:
  US09/679,280
• Time in Patent Office: 795 Days
• Field of Search: 356/39-42, 356/445-448, 356/73, 364/413.07, 436/164-172, 422/55, 422/56, 422/58, 422/82.05, 422/82.09
• US Class Current: 356/39
• 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
• 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 33/66 involving blood sugars, e.g. galactose

Abstract

A blood sugar measuring instrument for measuring the blood sugar level of blood on the basis of change in the color of the reagent having reacted with the blood. The instrument irradiates light onto a specimen to which blood is applied, detects the intensity of the reflected light with a photo detector, determines absorbency from the specimen every one second after the specimen has started coloring by the applied blood, and calculates the blood sugar level of the blood applied to the specimen on the basis of the absorbency when change in the absorbency has become 2% or less.

Claims

1. A blood sugar measuring instrument for measuring blood sugar level of blood impregnated in a reagent layer of a specimen, said instrument comprising:

irradiation means for irradiating light towards the reagent layer;

reflected light detecting means for detecting an intensity of the light reflected from the reagent layer;

calculation means for calculating a change of the intensity per each second, based on the intensity detected by the reflected light detecting means over a plurality of seconds;

determination means for determining whether or not the change of the intensity calculated by the calculating means has become a first predetermined value or less; and

blood sugar calculating means for calculating the blood sugar level of said blood on the basis of the intensity of the light reflected from the reagent layer when the determination means determines that the change has become the first predetermined value or less.

2. The blood sugar measuring instrument according to claim 1, wherein said determination means detects whether or not the change of the intensity has become a first predetermined value or less on the basis of absorbency obtained from the intensity of the reflected light from said specimen before reacting with said blood, and the intensity of the reflected light after said specimen has been colored by the reaction with said blood.

3. The blood sugar measuring instrument according to claim 1, further comprising:

notifying means for notifying that the blood sugar level is measuring; and

notifying control means for controlling a mode of notification of said notifying means to change the mode when the change of the intensity becomes larger than said first predetermined value, and becomes a second predetermined value which is present before said first predetermined value.

4. The blood sugar measuring instrument according to claim 3, wherein said notifying control means further notifies that measurement is started when coloration of said specimen is detected.

5. The blood sugar measuring instrument according to claim 1, wherein said specimen has:

an opening for applying blood,

a traveling portion to which blood applied to said opening travels, and

a reagent layer portion colored by the reaction with blood having passed through said traveling area, and that said reflected light detecting means detects reflected light from said reagent layer portion.

6. The blood sugar measuring instrument according to claim 5, wherein said reagent layer portion comprises a reagent layer which is colored by the reaction with blood, and a filter layer for filtering blood cells of the blood.

7. The blood sugar measuring instrument according to claim 5, wherein an initial color of said reagent layer portion is substantially white.

8. The blood sugar measuring instrument according to claim 3, wherein said notifying means moves and displays a predetermined mark at a predetermined speed, and said notifying control means changes a speed of movement of said predetermined mark when said second predetermined quantity is reached.

19. The blood sugar measuring instrument according to claim 1, wherein the plurality of seconds is two seconds to six seconds.

9. A method for measuring blood sugar level of blood impregnated to a reagent layer of a specimen comprising:

directing light toward the reagent layer;

detecting an intensity of light reflected from the reagent layer;

calculating a change of the intensity each second based on the intensities detected over a plurality of seconds;

determining whether the change has reached a first predetermined value or less;

calculating the blood sugar level of the blood based on the intensity of light reflected from the reagent layer when the change has reached the first predetermined value or less.

10. The method for measuring the blood sugar level of blood according to claim 9, wherein the change is determined based on absorbency obtained from the intensity of the light reflected from the specimen before reacting with the blood and the intensity of the light reflected from the specimen after the specimen has been colored by the reaction with the blood.

11. The method for measuring the blood sugar level of blood according to claim 9, further comprising:

providing notification by way of a notification mode that the blood sugar level is being measured; and

changing the notification mode when the change becomes larger than said first predetermined value and has reached a second predetermined value which is present before the first predetermined value.

12. The method for measuring the blood sugar level of blood according to claim 11, wherein the notification includes providing notification that measurement of the blood sugar is started when coloration of the specimen is detected.

13. The method for measuring the blood sugar level of blood according to claim 9, wherein the specimen includes an opening for applying blood, a traveling area to which travels blood applied to the opening, and a reagent layer portion colored by reaction with blood that has passed through the traveling area, the method including detecting light reflected from the reagent layer portion.

14. The method for measuring the blood sugar level of blood according to claim 13, wherein the reagent layer portion comprises a reagent layer which is colored by reaction with the blood, and a filter layer for filtering blood cells of the blood.

15. The method for measuring the blood sugar level of blood according to claim 13, wherein an initial color of the reagent layer portion is substantially white.

16. The method for measuring the blood sugar level of blood according to claim 11, wherein the notification includes moving a predetermined mark at a predetermined speed and displaying the predetermined mark, and the changing of the notification mode including changing the speed of movement of the predetermined mark when the second predetermined quantity is reached.

17. The method for measuring the blood sugar level of blood according to claim 11, wherein the changing of the notification mode includes changing the second predetermined quantity corresponding to a measured glucose concentration.

18. The method for measuring the blood sugar level of blood according to claim 9, including measuring ambient temperature and determining the blood sugar level based in the measured ambient temperature.

20. The method for measuring the blood sugar level of blood according to claim 9, wherein the calculation of the change of the intensity per each second is based on the intensities detected between two seconds to six seconds.