Method of determining a concentration of an analyte in a bodily fluid

A method of determining a concentration of an analyte in a body fluid with a mobile device having a camera, the method comprising:

• a) prompting a user to perform one or more of applying body fluid to a test field of an optical test strip and confirming application of the application of body fluid to the test field;
• b) waiting a predetermined minimum waiting time;
• c) using the camera to capture an image of at least part of the test field having the body fluid applied thereto;
• and
• d) determining the concentration of the analyte in the bodily fluid based on the image captured in step c), step d) further comprising:
• i) estimating a point in time of sample application to the test field by taking into account a first item of time-dependent information derived from the image captured in step c) using a first color channel of a color space;
• and
• ii) estimating the concentration of the analyte by taking into account a second item of concentration-dependent information derived from the image using a second color channel of the color space, wherein the estimating of the concentration of the analyte in the bodily fluid further takes into account the estimated point in time of sample application;
• e) a refining step, comprising:
• assessing plausibility of the estimated analyte concentration determined in step ii) using the first item of information,
• improving accuracy of the estimated analyte concentration determined in step ii) using the first item of information,
• wherein the method further includes:
• the second item of information is time-dependent, wherein, in step ii) the concentration of the analyte is estimated using an assumed time span elapsed from the time of application of the body fluid, wherein the first item of information, in addition to being time-dependent, is dependent on the analyte concentration, wherein, in step e), the dependency of the first item of information on the concentration is eliminated by assuming the concentration of the analyte in the body fluid estimated in step ii), thereby deriving a probable time span elapsed from the time of the application of the body fluid to the test field from the first item of information, wherein the probable time span elapsed is compared with the assumed time span elapsed,
• step e) comprises applying a correction to the estimated analyte concentration, wherein the correction comprises applying a correction factor to the estimated analyte concentration and/or applying an offset to the estimated analyte concentration, wherein the correction to the estimated analyte concentration is a function of a time variable characterizing a time span elapsed between the application of the body fluid and the capturing of the image of the test field, with the test field having the bodily fluid applied thereto.