Latex particles for measurement reagents, sensitized latex particles, and measurement reagent for turbidimetric immunoassay

Latex particles for measurement reagents having a coefficient of variation in particle diameters of 10% or less and an average particle diameter of 250 nm to 1000 nm,

• wherein the latex particles each contain 20% by weight or more of a compound having a refractive index of 1.60 or more,
• the depth of a supernatant is 5 mm or less when a liquid dispersion having a solid matter concentration of 1% by weight, which is prepared by dispersing the latex particles in ultrapure water, is placed in a 10-ml measuring cylinder having a body inner diameter of 10.8 mm and is then left for 10 days,
• wherein the compound having a refractive index of 1.60 or more includes a compound having at least one skeleton selected from the group consisting of a fluorene skeleton, a dinaphthothiophene skeleton, a naphthalene skeleton, an anthracene skeleton and a phenanthrene skeleton,
• wherein the latex particles have a porous hollow structure having two or more hollow structures.