Abstract: The current subject matter can include non-invasive systems and methods for detecting hemoglobin. In one implementation, a method includes receiving data characterizing a plurality of images associated with palpebral conjunctiva region of one or more patients. The method also includes receiving data indicative of a user selection of a first pixel of a first image of the plurality of images. The method further includes determining, a region of interest associated with the selected first pixel. The determining can include identifying a plurality of pixels adjacent to the first pixel having color parameter values within a predetermined range of a first color parameter value of the first pixel. The method also includes determining a first plurality of parameters associated with the region of interest, and providing the first plurality of parameters.

Abstract: A method of estimating an amount of a substance in a bodily fluid from the color of a tissue surface of a subject includes capturing an image including at least a portion-of-interest of the subject and at least a reference portion of a color reference, the image being a digital image of pixels of at least one color, the image including a component value for each pixel for each of the at least one color, obtaining a first value associated with at least one component value corresponding to the portion-of-interest of the subject, obtaining a second value associated with at least one component value corresponding to the reference portion, and calculating an estimated amount of the substance using the first and second values.

Abstract: A method of estimating an amount of a substance in a bodily fluid from the color of a tissue surface of a subject includes capturing an image including at least a portion-of-interest of the subject and at least a reference portion of a color reference, the image being a digital image of pixels of at least one color, the image including a component value for each pixel for each of the at least one color, obtaining a first value associated with at least one component value corresponding to the portion-of-interest of the subject, obtaining a second value associated with at least one component value corresponding to the reference portion, and calculating an estimated amount of the substance using the first and second values.