Patent ID: 7897409

Claim:
A dilution cup, comprising: a cup member having an inner face comprising a surface of rotation, wherein a diameter of a portion of the inner surface increases from a bottom to a top of the inner surface in the direction of the axis of the surface of rotation; an opening portion surrounding an opening, where a sample solution is dispensed, located on or near the top; a reagent aperture portion surrounding an aperture where a reagent is dispensed, whereby a mixed solution of the sample solution and the reagent may be held in the cup member; and a drain aperture portion surrounding a drain aperture, where a mixed solution of the sample solution and the reagent is discharged, located on or near the bottom, wherein the reagent aperture portion is located in the portion of the inner surface whose diameter increases from a bottom to a top of the inner surface, and above the drain aperture portion, and wherein the reagent aperture portion is oriented horizontally and with a direction of flow that is shifted from the axis of the surface of rotation, whereby the reagent dispensed by the reagent aperture portion forms a spiral flow that spirals upward from the reagent aperture portion.