HYDROPHILIC COLORING CELLULOSE MICROPARTICLES

Provided are: a coloring cellulose microparticle enabling false positive to be significantly reduced while maintaining a high detection sensitivity; and an immunochromatographic diagnostic kit using the same. The present invention provides: a coloring cellulose microparticle characterized in that an average particle diameter is 60-900 nm, a coloring intensity is 1.0-10.0, and a hydrophilic layer is provided on the surface of microparticle, and a carboxyl group is introduced onto the surface of the microparticle with a spacer therebetween; a structure in which a ligand is covalently bonded to the carboxyl group of said coloring cellulose microparticle; and an immunochromatographic diagnostic kit including said structure.