Organic coloring fine particles, diagnostic kits and in vitro diagnostic method comprising the same

Is highly sensitive and capable immunochromatography kit multicolor, and the provision of suitable organic colored particles as a component of the kit. Average particle diameter of 10 nm to 1000 nm, and color intensity are an organic coloring fine particles, which is a 1.0 to 5.0, thereby preparing a cellulose as a starting material. Such organic coloring fine particles was used as labels in immunochromatography kit, be a highly sensitive immunochromatography kit was found as compared to the prior art. Immunochromatography kit according to the present invention, multi-color development are possible and useful for rapid diagnosis.