A method for analyzing a digital image containing the result of an agglutination assay to generate a quantitative result value representative of the degree of agglutination of the sample is provided. The method for analyzing the digital image includes: applying a filter to extract a component of the image or portion of a spectrum where a signal to noise ratio between agglutinated and background is maximized; extracting a set of features that characterize the agglutination pattern, obtaining a quantification function which maps measured features to the actual concentration of the sample and computing a quantitative result for each sample in the assay.