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EP-4736122-A1 - A METHOD FOR DETERMINING A TEST RESULT OUTCOME BY USING A MOBILE DEVICE

EP4736122A1EP 4736122 A1EP4736122 A1EP 4736122A1EP-4736122-A1

Abstract

It is disclosed a computer-implemented method (800) for determining a test result outcome by using a mobile device (100) equipped with a camera (102) arranged to capture image data depicting a test arrangement (106). The method comprises obtaining (802) the image data using the mobile device (100), identifying (804) a colour reference section (CRS) (114) in the image data, wherein the CRS (114) is coloured with at least one reference colour (), determining (806) a camera response function specific for a mobile device type associated with the mobile device () by, for each of a plurality of different exposure times, registering (808) a camera response for the at least one reference colour, wherein said camera response corresponds to a photon flux, and combining (810) the camera responses for the plurality of different exposure times into the camera response function, obtaining (812) a test image data set depicting a test section (122) of the test arrangement (106), wherein the test section (122) is coloured differently for different test result outcomes, transforming (814) the test image data set into a camera-neutral test image data set by using the camera response function, determining (816) an intensity of a test object (124), such as a test line or a test dot, in the test section (122) based on the camera-neutral test image data set, and determining (818) the test result outcome by fitting the intensity to a calibration curve, wherein the test result outcome corresponds to a concentration of an analyte held in the test section (122).

Inventors

  • THORSTENSEN, Jostein
  • ZONETTI, Simone
  • SIKORSKI, KRZYSZTOF
  • MØRK, Einar

Assignees

  • Calpro AS

Dates

Publication Date
20260506
Application Date
20240627

Claims (15)

  1. 1. A computer-implemented method (800) for determining a test result outcome by using a mobile device (100) equipped with a camera (102) arranged to capture image data depicting a test arrangement (106), the method comprising obtaining (802) the image data using the mobile device (100), identifying (804) a colour reference section CRS (114) in the image data depicting the test arrangement (106), wherein the CRS (114) is coloured with at least one reference colour, determining (806) a camera response function specific for a mobile device type associated with the mobile device (100) by for each of a plurality of different exposure times, registering (808) a camera response for the at least one reference colour, wherein said camera response corresponds to a photon flux, combining (810) the camera responses for the plurality of different exposure times into the camera response function, obtaining (812) a test image data set depicting a test section (122) of the test arrangement (106), wherein the test section (122) is coloured differently for different test result outcomes, transforming (814) the test image data set into a camera-neutral test image data set by using the camera response function, determining (816) an intensity of a test object (124), such as a test line or a test dot, in the test section (122) based on the camera-neutral test image data set, and determining (818) the test result outcome by fitting the intensity to a calibration curve, wherein the test result outcome corresponds to a concentration of an analyte held in the test section (122).
  2. 2. The method according to claim 1, said test arrangement (106) comprising a test cassette (110) placed inside a test frame (108), wherein the CRS (114) is provided on the test frame (108) and the test section (122) is provided on the test cassette (110).
  3. 3. The method according to claim 1 or 2, wherein the test arrangement (106) is provided with at least one two-dimensional code (112a, 112b, 128), such as an AruCo code, for facilitating spatial alignment of the camera (102) of the mobile device (100) with respect to the test arrangement (106).
  4. 4. The method according to any one of the preceding claims, wherein the at least one reference colour comprises a bright colour (118) and a dark colour (116), wherein the camera response for the bright colour is greater than the camera response for the dark colour.
  5. 5. The method according to any one of the preceding claims, further comprising, prior to the step of identifying the CRS (114), activating (820) a flash (104) on the camera (102) to reduce variance in illumination.
  6. 6. The method according to any one of the preceding claims, wherein the CRS (114) is matte to reduce impact of reflections.
  7. 7. The method according to any one of the preceding claims, further comprising, prior to the step of identifying (804) the CRS (114), detecting (822) movement of the camera (102) by using an accelerometer provided in the mobile device (100), in case the movement is below a threshold, continue with the identifying of the CRS.
  8. 8. The method according to any one of the preceding claims, wherein obtaining (802) the image data, identifying (804) the CRS (114), determining (806) the camera response function and capturing (812) the at least one test image data set are performed within a time span of less than 1 second such that effects of changes in light conditions are reduced.
  9. 9. A test arrangement (106) comprising a sample reception section (120) for receiving a test liquid sample, a test section (122) configured to be coloured differently for different test result outcomes, and to display a test object, such as a test line or a test dot, at least one colour reference section (CRS) (114) coloured with at least one reference colour providing for that a camera response function specific for a mobile device type of a mobile device equipped with a camera can be determined by using a plurality of different exposure times for the camera, in turn providing for that test image data depicting the test section (122) can be transformed into a camera-neutral test image data set by using the camera response function, in turn providing for that an intensity of the test object (124) can be determined based on the camera-neutral test image data set, in turn providing for that a test result outcome can be determined by fitting the intensity to a calibration curve, wherein the test result outcome corresponds to a concentration of an analyte held in the test section (124).
  10. 10. The test arrangement (106) according to claim 9, further comprising a test cassette (110) arranged to be placed inside a test frame (108), wherein the CRS (114) is provided on the test frame (108) and the test section (122) is provided on the test cassette (110).
  11. 11. The test arrangement (106) according to claim 9 or 10, further comprising at least one two-dimensional code (112a, 112b, 128), such as an AruCo code, for facilitating spatial alignment of the camera (102) of the mobile device (100) with respect to the test arrangement (106).
  12. 12. The test arrangement (106) according to claim 11 , wherein a position of the CRS relative to a position of the at least one two-dimensional code is pre-set such that the position of the CRS can be determined based on the position of the at least one code.
  13. 13. The test arrangement (106) according to any one of the claims 9 to 12, wherein the at least one reference colour comprises a bright colour (118) and a dark colour (116), wherein the camera response for the bright colour is greater than the camera response for the dark colour.
  14. 14. A mobile device (100) comprising a processor device, a memory and a camera (102), wherein the processor device is configured to obtain the image data using the camera (102), identify a colour reference section CRS (114) in the image data depicting a test arrangement (106), wherein the CRS (114) is coloured with at least one reference colour, determine a camera response function specific for a mobile device type associated with the mobile device (100) by for each of a plurality of different exposure times, register a camera response for the at least one reference colour, wherein said camera response corresponds to a photon flux, combine the camera responses for the plurality of different exposure times into the camera response function, obtain a test image data set depicting a test section (122) of the test arrangement (106), wherein the test section (122) is coloured differently for different test result outcomes, transform the test image data set into a camera-neutral test image data set by using the camera response function, determine an intensity of a test object (124), such as a test line or a test dot, in the test section (122) based on the camera-neutral test image data set, and determine the test result outcome by fitting the intensity to a calibration curve, wherein the test result outcome corresponds to a concentration of an analyte held in the test section (122).
  15. 15. A system for determining a test result outcome by analysing image data depicting a test arrangement (106), said system comprising a server and a mobile device (100) equipped with a camera (102), wherein the system is configured to obtain the image data using the camera (102), identify a colour reference section CRS (114) in the image data depicting a test arrangement (106), wherein the CRS (114) is coloured with at least one reference colour, determine a camera response function specific for a mobile device type associated with the mobile device (100) by for each of a plurality of different exposure times, register a camera response for the at least one reference colour, wherein said camera response corresponds to a photon flux, combine the camera responses for the plurality of different exposure times into the camera response function, obtain a test image data set depicting a test section (122) of the test arrangement (106), wherein the test section (122) is coloured differently for different test result outcomes, transform the test image data set into a camera-neutral test image data set by using the camera response function, determine an intensity of a test object (124), such as a test line or a test dot, in the test section (122) based on the camera-neutral test image data set, and determine the test result outcome by fitting the intensity to a calibration curve, wherein the test result outcome corresponds to a concentration of an analyte held in the test section (122).

Description

A METHOD FOR DETERMINING A TEST RESULT OUTCOME BY USING A MOBILE DEVICE Technical Field The invention relates to rapid tests, e.g. lateral flow immunoassay tests, and how these tests can be read by using a mobile phone application or the like. More particularly, it is related to a computer-implemented method for determining a test result outcome based on image data depicting a test arrangement by using a mobile device, as well as a test arrangement and a mobile device. Background Art During the last couple of years, using rapid tests in combination with mobile phone applications for distant monitoring purposes have gained an increasing interest. By having the rapid tests, often based on lateral flow immunoassay principles, and the mobile phone application, it is possible for a patient to perform tests in a reliable manner from home, which is both convenient and cost-efficient. In addition, by increasing the accessibility, it is also made possible to perform tests more frequently, thereby providing more information about the patient, which in turn provides for improved treatment. For instance, by using this approach, symptoms can be detected at an early stage, which provides for that treatment may be initiated at an earlier stage compared to if the patient is seeking a doctor’s appointment once the symptoms are obvious. As an example, the company Calpro is offering CalproSmart™, a self-test for monitoring patients suffering from chronic inflammatory bowel disease (IBD), such as Ulcerative Colitis and Crohn’s disease. The test is based on Calprotectin, an inflammatory biomarker. Since this biomarker will increase 3-6 months before clinical symptoms can be detected, this test provides for that it is possible to detect and treat IBD at an early stage. To provide for that a test result outcome, that is, to what extent the biomarker is increased, is determined and forwarded to a remote server, the mobile phone application can be used. The general approach of this is capturing image data depicting a test section of a test cassette by using a camera of the mobile phone, processing the image data such that the extent the biomarker is increased is quantified, and transmitting the test result outcome to the remote server such that the information can be made available for further analysis by a healthcare professional. Several techniques are available for determining the test result outcome based on the image data depicting the test section by using a mobile phone or the like. For instance, in order to provide for the test section in the test cassette can be identified in a reliable manner, a test frame can be used. The test frame is provided with a cut-out having the same contour as the test cassette such that the test cassette can be fitted into the frame. The test frame may be provided with reference markings such that the test frame can be identified via the captured image data. Even though there are different mobile applications for reading and determining test result outcomes available today, there are still improvements to be made. For instance, there is a need for improved accuracy. By being able to determine changes in the test section more accurately, it is namely made possible to make more reliable conclusions based on the test result outcome. It is an object of the invention to at least partly overcome one or more of the above-identified limitations of the prior art. In particular, it is an object to provide a method for determining the test result outcome that is less device dependent. Today, many mobile phones are configured to provide image data that are considered appealing by users, but not necessarily configured to provide image data that consistently and correctly reflects changes. For instance, a change in luminosity of the test line in the test section may give rise to different image data output by different camera-equipped mobile phones. Since the changes of the test line corresponds to the increase of the biomarker, using different types of mobile phones for determining the test result outcome may therefore result in that different outcomes are provided, which negatively affects the reliability. According to a first aspect it is provided a computer-implemented method for determining a test result outcome by using a mobile device equipped with a camera arranged to capture image data depicting a test arrangement. The method may comprise obtaining the image data using the mobile device, identifying a colour reference section CRS in the image data depicting the test arrangement, wherein the CRS is coloured with at least one reference colour, determining a camera response function specific for a mobile device type associated with the mobile device by for each of a plurality of different exposure times, registering a camera response for the at least one reference colour, wherein said camera response corresponds to a photon flux, combining the camera responses for the plurality of different expos