1. A method of analysis of an agglutination reaction producing an agglutination pattern, the analysis method comprising the steps of: (a) photoelectrically capturing an image of the agglutination pattern; (b) digitizing the image captured to form a digital image comprising a pixel; (c) measuring roughness, reflecting pixel local environment, at each pixel comprising a region of interest of the digital image of the agglutination pattern; and (d) performing at least one of classification and quantification of the image captured of the agglutination pattern based on the measured roughness.