METHOD OF DETERMINING A CONCENTRATION OF AN ANALYTE IN A BODY FLUID

Abstract

A method of determining concentration of an analyte in a body fluid using a mobile device having a camera is disclosed. In the inventive method, angular orientation of the mobile device relative to the test element is determined by using sensor data of a sensor integrated into the mobile device. The angular orientation of the mobile device relative to the test element is subjected to a validity test. Taking into account the result of the validity test, an image of at least part of a test strip is captured and concentration of analyte in a body fluid sample applied to the test strip can be determined.

Claims

1. A method of determining concentration of an analyte in a body fluid by using a mobile device having a camera and using a test element having a test field, the method comprising: a) determining an angular orientation of the mobile device relative to the test element by using sensor data of a sensor integrated into the mobile device; b) subjecting the angular orientation to a validity test; c) retrieving an image stream using the camera, wherein at least a part of the images of the image stream are flagged with an item of information regarding whether the image was retrieved at a point in time for which the validity test determines the angular orientation of the mobile device relative to the test element to be valid; d) capturing a still image of at least part of the test field separately from the image stream by using a still image mode of the camera, wherein the still image provides enhanced spatial resolution and/or higher dynamics compared to the images from the image stream, wherein the capturing of the still image is initiated automatically when an image of the image stream was flagged with an item of information indicating a valid image at a point in time for which the image of the image stream was flagged as being valid; and e) determining the concentration of the analyte in the body fluid from the image based at least partially on the still image; wherein at least one of steps d) and e) is performed by taking into account the result of the validity test of step b).

2. The method according to claim 1, wherein the validity test in step b) comprises comparing the angular orientation of the mobile device relative to the test element with a target orientation, wherein the validity test determines the angular orientation of the mobile device relative to the test element to be: valid when the angular orientation deviates from the target orientation by no more than a predetermined angular tolerance; and invalid when the angular orientation deviates from the target orientation by more than the predetermined angular tolerance.

3. The method according to claim 1, further comprising monitoring the angular orientation of the mobile device relative to the test element and (i) blocking the capturing of the image when the validity test determines the angular orientation of the mobile device relative to the test element to be invalid, and (ii) automatically capturing the image when the validity test determines the angular orientation of the mobile device relative to the test element to be valid.

4. The method according to claim 1, wherein step a) at least partially is performed under the assumption that the test element is oriented in a predetermined orientation.

5. The method according to claim 1, wherein the method further comprises determining the angular orientation of the test element by placing the mobile device on a support surface and determining the angular orientation of the support surface, wherein, in step a), the test element is placed on the support surface.

6. The method according to claim 1, wherein the method further comprises applying a sample of the body fluid to the test element, wherein step c) further comprises capturing a dry reference image of the at least one part of the test element before applying the body fluid to the test element and capturing a measurement image of the at least one part of the test element after applying the body fluid to the test element, wherein, in step d), both the dry reference image and the measurement image are taken into account for determining the concentration of the analyte in the body fluid.

7. The method according to claim 1, wherein the method comprises providing user guidance for guiding a user towards a target orientation of the mobile device relative to the test element.

8. The method according to claim 1, wherein the method does not imply a mathematical correction of the image for angular misalignment.

9. A mobile device having a camera, a sensor and a processor configured to determining concentration of an analyte in a body fluid by using the method according to claim 1.

10. A kit comprising a mobile device according to claim 9, the kit further comprising at least one test element having a test field.

11. The kit according to claim 10, further comprising a reference card having at least one reference color field.

12. A non-transitory computer readable medium having stored thereon computer executable instructions for performing the method according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0134] The above-mentioned aspects of exemplary embodiments will become more apparent and will be better understood by reference to the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0135] FIG. 1 shows a perspective view of an embodiment of a kit and a mobile device;

[0136] FIG. 2 shows an embodiment of an image of a part of the test element captured by a camera of the mobile device;

[0137] FIG. 3 shows a flow chart of a method of determining a concentration of at least one analyte in a body fluid by using a mobile device and a test element;

[0138] FIG. 4 shows a top plane view of an embodiment of a mobile device; and

[0139] FIG. 5 shows an embodiment of a graph of backscattered intensity over a polar angle.

DESCRIPTION

[0140] The embodiments described below are not intended to be exhaustive or to limit the invention to the precise forms disclosed in the following detailed description. Rather, the embodiments are chosen and described so that others skilled in the art may appreciate and understand the principles and practices of this disclosure.

[0141] In FIG. 1 a perspective view of an embodiment of a kit 110 and a mobile device 112 is shown. The kit 110 comprises the mobile device 112 and at least one test element 114 having at least one test field 116. The mobile device 112 comprises a camera 118 and is configured for determining a concentration of at least one analyte in a body fluid by using the test element 114. Specifically, the mobile device 112 is configured to perform the method of determining a concentration of at least one analyte in a body fluid. In particular, at least one sensor device 120 may be integrated into the mobile device 112. Sensor data of the at least sensor device 120 may be used for determining an angular orientation of the mobile device 112 relative to the test element 114. As an example, an angle θ between a normal direction 122 of the test element 114 and an image capturing direction 124 of the camera of the mobile device 112 may be determined. The mobile device 112 may further comprise at least one processor 126. The processor 126 may for example be configured for processing the at least one image 128 of at least a part of the test element 114 captured by using the camera 118 of the mobile device 112.

[0142] In FIG. 2 an embodiment of an image 128 of a part of the test element 114 captured by using the camera 118 of the mobile device 112 is shown. The part of the test element 114 illustrated in the image 128 comprises at least one part of the test field 116 of the test element 114.

[0143] As illustrated in FIG. 1, the test element 114 may be placed on a support surface 130. In particular, an angular orientation 132 of the support surface may be determined, for example by placing the mobile device 112 on the support surface 130. As an example, additionally or alternatively to the normal direction 122 of the test element 114, the angular orientation 132 of the support surface may be used for determining the angle θ.

[0144] FIG. 3 shows a flow chart of a method of determining a concentration of at least one analyte in a body fluid by using a mobile device 112 and a test element 114. The method comprises the following steps, which may specifically be performed in the given order. Still, a different order may also be possible. It may be possible to perform two or more of the method steps fully or partially simultaneously. It may further be possible to perform one, more than one or even all of the method steps once or repeatedly. The method may comprise additional method steps which are not listed herein. The method steps of the method of determining a concentration of at least one analyte in a body fluid are the following: [0145] step a) (denoted with reference number 134) determining an angular orientation of the mobile device 112 relative to the test element 114 by using sensor data of at least one sensor device 120 integrated into the mobile device 112; [0146] step b) (denoted with reference number 136) subjecting the angular orientation of the mobile device 112 relative to the test element 114 to at least one validity test; [0147] step c) (denoted with reference number 138) capturing at least one image 128 of at least a part of the test element 114 by using the camera 118, the at least one part of the test element 114 comprising at least one part of the field 116; and [0148] step d) (denoted with reference number 140) determining the concentration of the analyte in the body fluid from the image 128;

[0149] At least one of steps c) and d) is performed by taking into account the result of the validity test in step b). In particular, the validity test in step b) may comprise comparing the angular orientation of the mobile device 112 relative to the test element 114 with at least one target orientation. Thus, the angular orientation of the mobile device 112 relative to the test element 114, as for example illustrated in FIG. 1, may be subjected to the at least one validity test. Specifically, the validity test may determine the angular orientation of the mobile device 112 relative to the test element 114 to be valid or to be invalid. In particular, in the validity test, the angular orientation of the mobile device 112 relative to the test element 114 may be compared to a target orientation. The angular orientation of the mobile device 112 relative to the test element 114 may specifically be valid in case the angular orientation deviates from the target orientation by no more than at least one predetermined angular tolerance. Alternatively, the angular orientation of the mobile device 112 relative to the test element 114 may be invalid in case the angular orientation deviates from the target orientation by more than the at least one predetermined angular tolerance. As an example, in the validity test, the angle θ may be compared to an angle of a target orientation with the predetermined angular tolerance. As an example, the target orientation may be parallel to the angular orientation of the mobile device 112. Thus, the angle of the target orientation may specifically be equal to 0°. For example, the angular orientation of the mobile device 112 may be targeted to be plane parallel to the angular orientation of the test element 114. Alternatively, the target orientation may be selected to be non-parallel to the angular orientation of the mobile device 112. It may particularly be useful for the target orientation, for example, to be equal to 10°. Specifically, the predetermined angular tolerance may be +/−10°. More specifically, the predetermined angular tolerance may be +/−5°. In particular, the predetermined angular tolerance may be +/−2°.

[0150] In FIG. 4, a top plane view of an embodiment of a mobile device 112 is shown. The mobile device 112 may specifically be in the process of performing the method of determining a concentration of at least one analyte in a body fluid, as illustrated in FIG. 3. The method may comprise monitoring the angular orientation of the mobile device 112 relative to the test element 114. Specifically, in case the validity test determines the angular orientation of the mobile device 112 relative to the test element 114 to be invalid, the method may further comprise blocking the capturing of the at least one image 128. However, in case the validity test determines the angular orientation of the mobile device 112 relative to the test element 114 to be valid, the method may comprise unblocking the capturing of the at least one image 128. Additionally or alternatively, the method may comprise automatically initiating the capturing of the at least one image 128 in case the validity test determines the angular orientation of the mobile device 112 relative to the test element 114 to be valid. Additionally or alternatively, the method comprises continuously retrieving an image stream by using the camera 118, wherein the capturing in step c) of the method may comprise selecting the at least one image 128 from the image stream. Specifically, the image 128 may be selected from the image stream in case the image 128 was retrieved at a point in time for which the validity test determines the angular orientation of the mobile device 112 relative to the test element 114 to be valid.

[0151] Further, the method may comprise providing user guidance for guiding a user towards a target orientation of the mobile device 112 relative to the test element 114. Specifically, the user guidance may comprise a visual guidance on a display 142 of the mobile device 112. As illustrated in FIG. 4, the visual guidance on the display 142 of the mobile device 112 may for example be a virtual outline 144 of the test strip 114. Additionally or alternatively, the visual guidance on the display 142 of the mobile device 112 may for example guide the user towards the target orientation of the mobile device 112 relative to the test element 114 by visually indicating in which direction the mobile device 112 is to be moved or tilted. In particular, the user guidance may make use of a spirit level function sensor. As an example, the visual guidance may comprise a visually illustrated ball 146 within a circle 148 shown on the display 142, wherein the user may be requested to guide the ball 146 towards the center of the circle 148. Specifically, the user may be requested to guide the ball 146 towards center of the circle 148 by moving and/or tilting the mobile device 112.

[0152] In FIG. 5 an embodiment of a graph of backscattered intensity over a polar angle is illustrated. The x-axis 150 shows a polar angle, specifically the angle θ, and the y-axis 152 shows the backscattered intensity I. In the graph, the dashed line illustrates a Lambertian reflectance 154, such as a reflectance of a surface which obeys Lambert's law, wherein the intensity observed from an ideal diffusely reflecting surface is directly proportional to the cosine of the angle θ between the direction of the incident light and the surface normal. In particular, when showing a Lambertian reflectance 154, a surface may have the same radiance when viewed from any angle θ. Thus, for example, the surface may have the same brightness or luminance at 0=20° and 0=−20°. In particular, the test field 116 of the test element 114 may for example show a Lambertian reflectance 154.

[0153] Further, in the graph, the solid line illustrates a measured reflectance 156, specifically a measured reflectance of for example the test element 114, such as for example a reflectance of a surface of the test element 114 except for the test field 116. As illustrated, the measured reflectance 156 shows a peak reflectance at −20°. In particular, the peak reflectance at −20° may have been unusual high width. A similar peak, though without the extremely high width, may be observed in the measured reflectance 156 at +20°. As an example, the peaks in the measured reflectance may interfere with a determination of the analyte in the body fluid from an image taken at −20° or +20°. Thus, it may be beneficial to avoid using such images for determining the analyte in the body fluid.

[0154] While exemplary embodiments have been disclosed hereinabove, the present invention is not limited to the disclosed embodiments. Instead, this application is intended to cover any variations, uses, or adaptations of this disclosure using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.

LIST OF REFERENCE NUMBERS

[0155] 110 kit [0156] 112 mobile device [0157] 114 test element [0158] 116 test field [0159] 118 camera [0160] 120 sensor [0161] 122 normal direction of the test element [0162] 124 image capturing direction [0163] 126 processor [0164] 128 image [0165] 130 support surface [0166] 132 angular orientation of the support surface [0167] 134 step a) [0168] 136 step b) [0169] 138 step c) [0170] 140 step d) [0171] 142 display [0172] 144 outline of the test strip [0173] 146 ball [0174] 148 circle [0175] 150 x-axis [0176] 152 y-axis [0177] 154 Lambertian reflectance [0178] 156 measured reflectance