Reading test strip with reaction area, color calibration area, and temperature calibration area

• US 9,600,878 B2
• Filed: 05/14/2015
• Issued: 03/21/2017
• Est. Priority Date: 04/06/2012
• Status: Active Grant

• Current Assignee: iXensor Co., Ltd
• Original Assignee: iXensor Inc.
• Inventors: Tsai, Tungmeng, Chen, Chieh Hsiao, Chen, Yenyu
• Primary Examiner(s): Mui, Christine T
• Application Number:
  US14/711,794
• Publication Number:
  US 20150254844A1
• Time in Patent Office: 677 Days
• Field of Search: 436/95, 436/94, 436/93, 436/91
• US Class Current: 1/1
• CPC Class Codes: G01N 2021/8488 the band presenting reference patches
• CPC Class Codes: G01N 21/78 producing a change of colour
• 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 33/48771 Coding of information, e.g. calibration data, lot number
• CPC Class Codes: G01N 33/5094 for blood cell populations red blood cells G01N33/80
• CPC Class Codes: G01N 33/52 Use of compounds or compositions for colorimetric, spectrophotometric or fluorometric investigation, e.g. use of reagent paper and including single- and multilayer analytical elements immunological elements G01N33/54386; involving labelled immunochemicals G01N33/58; for haemoglobin or occult blood G01N33/72
• CPC Class Codes: G01N 33/66 involving blood sugars, e.g. galactose
• CPC Class Codes: G06F 18/22 Matching criteria, e.g. proximity measures
• CPC Class Codes: G06T 7/0012 Biomedical image inspection
• CPC Class Codes: G06T 7/90 Determination of colour characteristics
• CPC Class Codes: Y10T 436/144444 Glucose

Abstract

A method is provided for a computing device with an imaging device to read a specimen test strip. The method includes capturing an image of the specimen test strip, wherein the image includes a reaction area, a color calibration area, and a temperature calibration area on the specimen test strip, determining a color of the reaction area based on one or more colors of the color calibration area, and determining a value of a characteristic of an analyte by correlating the color of the reaction area to the value and then adjusting the value based on the color of the temperature calibration area, or adjusting the color of the reaction area based on the color of the temperature calibration area and then correlating the color of the reaction area to the value.

Claims

1. A method for a computing device with an imaging device to read a specimen test strip to detect a characteristic of an analyte in a specimen sample, comprising:

capturing an image of the specimen test strip under a set of imaging conditions,

wherein;

the image includes a reaction area, a color calibration area, and a temperature calibration area on the specimen test strip;

the reaction area has a color based on the characteristic of the analyte;

the color calibration area having one or more colors; and

the temperature calibration area has a color based on its temperature;

determining the color of the reaction area by comparing the reaction area with the one or more colors of the color calibration area in the image captured under the set of imaging conditions; and

determining a value of the characteristic of the analyte, comprising;

correlating the color of the reaction area to the value of the characteristic of the analyte and then adjusting the value of the characteristic of the analyte based on the color of the temperature calibration area;

or

adjusting the color of the reaction area based on the color of the temperature calibration area and then correlating the color of the reaction area to the value of the characteristic of the analyte.

2. The method of claim 1, wherein:

determining the color of the reaction area comprises determining a color intensity in addition to determining the color of the reaction area based on the one or more colors of the color calibration area; and

correlating the color of the reaction area comprises correlating the color intensity in addition to correlating the color of the reaction area to a value of the characteristic of the analyte.

3. The method of claim 2, further comprising selecting a steady image from multiple images as the image for determining the color or the color and the color intensity of the reaction area.

4. The method of claim 1, wherein the image comprises a frame of a video.

5. The method of claim 1, further comprising:

determining if an illumination of the image is uniform from at least two locations on the color calibration area; and

when the illumination of the image is not uniform, correcting the illumination'"'"'s effect on the image.

6. The method of claim 5, wherein correcting the illumination'"'"'s effect on the image comprises:

determining an illumination profile from the at least two locations on the color calibration area;

estimating RGB values of the illumination profile at a pixel in the reaction area; and

determining corrected RGB values of the pixel as follows;

RGBnew=i*(R(x,y), G(x,y), B(x,y))/(Rest(x,y), Gest(x,y), Best(x,y)),

where R(x,y), G(x,y), B(x,y) are the original RGB values of the pixel, Rest(x,y), Gest(x,y), Best(x,y) are the estimated RGB values of the illumination profile at the pixel, and i is the maximum RGB values of a color in the reaction area.

7. The method of claim 2, wherein the image further includes an other reaction area on the specimen test strip, and the method further comprises correcting the color or the color and the color intensity of the reaction area based on the other calibration area.

8. The method of claim 7, wherein the reaction area detects a glucose level and the other reaction area detects a hematocrit level.

9. The method of claim 1, further comprising:

directing a light through a top opening of a hole in a path of the specimen sample in the specimen test strip;

determining a color of the light exiting from a bottom opening of the hole or reflected out from the top opening;

correlating the color of the light to an other value of an other analyte characteristic; and

correcting the color of the reaction area based on the other value of the other analyte characteristic.

10. The method of claim 9, wherein the analyte characteristic is a glucose level and the other analyte characteristic is a hematocrit level.

11. The method of claim 1, wherein the image further includes a timer on the specimen test strip, and the method further comprises determining when to capture the image based on the timer.

12. The method of claim 11, wherein the timer comprises a timer capillary.

13. The method of claim 11, wherein the timer comprises a timer area that receives the specimen sample and changes color linearly in response to the specimen sample.

14. The method of claim 11, wherein the timer comprises a timer area that changes color in response to light or humidity when the specimen test strip is removed from a package.

15. The method of claim 2, wherein:

determining the color or the color and the color intensity of the reaction area based on the one or more colors of the color calibration area comprises determining a first color component of the reaction area after determining a second color component of the reaction area indicates an appropriate time to read the first color component of the reaction area; and

correlating the color or the color and the color intensity of the reaction area to the value of the characteristic of the analyte comprises correlating the first color component to the value of the characteristic of the analyte.

16. The method of claim 1, further comprising:

capturing an image of a meal at a time;

associating the image of the meal, the time, and the value of the characteristic of the analyte; and

displaying or transmitting an association of the image of the meal, the time, and the value of the characteristic of the analyte.