Another embodiment of the present disclosure is a method for detecting the presence of erythrocytes in a sample derived from a subject, the method including the steps of:

- analyzing the quality control substance described in the section of <Quality Control Substance> described above, using a urine sediment analyzer, in order to determine the form of the artificial particles in the quality control substance;
- analyzing the sample derived from the subject and containing sediments, using the urine sediment analyzer;
- comparing the form of the artificial particles in the quality control substance with the forms of the sediments in the sample; and
- determining the presence of erythrocytes in the sample, if any of the forms of the sediments in the sample matches the form of the artificial particles in the quality control substance.

The “subject” refers to an individual who undergoes the examination of sediments in a sample derived from the individual. The subject may be an individual with a disease, an individual suspected to have a disease, or a healthy individual. The subject is preferably a human being.

The sample is not particularly limited as long as the sample possibly contains erythrocytes. Examples of the sample include urine and blood. Of these, urine is preferred.

Whether or not the form of erythrocytes in the sample matches the form of the artificial particles in the quality control substance can be automatically determined by the urine sediment analyzer to be used. For example, in the case of using the urine sediment analyzer disclosed in Patent Document 2, which is based on an unstained image analysis performed in a fluid, the analyzer that identifies the types of sediments extracts the feature values (such as color, form and particle size) of the artificial particles in the quality control substance from the images of the artificial particles, and stores the feature values thereof as the feature values of erythrocytes in the urine sediment analyzer, in advance. In the case of automatically identifying the sediments in the sample, the above-described analyzer extracts the feature values of the respective sediments in the sample from the images of the sediments; performs a pattern matching with the feature values of erythrocytes, which had been stored in the urine sediment analyzer in advance, to determine whether or not any of the forms of the sediments matches the form of erythrocytes (namely, whether or not the degree of similarity between the forms of both is equal to or higher than a certain value); and indicates the presence of erythrocytes in the sample, if it is determined that the forms of both match with each other.

Further, the urine sediment analyzer may count the number of erythrocytes detected.

The definition of the urine sediment analyzer includes a urine sediment analyzer based on a microscope. The urine sediment analyzer based on a microscope may be, for example, AUTION EYE® AI-4510 (manufactured by Arkray, Inc.).

By detecting the presence of erythrocytes in a sample derived from a subject, or by the result of counting the number of erythrocytes in the sample derived from the subject, it is possible to suspect the presence of a disease such as nephritis, and to determine a treatment plan (for example, the administration of a drug) for such a disease, as necessary.

EXAMPLES

Examples are described for the purpose of disclosure, and are not intended to limit the scope of the present disclosure.

Example 1

At room temperature, polyoxyethylene (20) sorbitan monolaurate (Tween® 20; manufactured by FUJIFILM Wako Pure Chemical Corporation) having a final concentration of 0.01% was added to PBS (pH 7.4) (27575-31, manufactured by Nakalai Tesque, Inc.) (lx concentration), and the mixture was stirred. To the resulting solution, NH-RAS06 (manufactured by Nikko Rica Corporation) (final concentration: 1.0×10^<4mg/mL), which is a raspberry-like, alumina microparticle-encapsulated silicone powder having an average particle size of 6 μm, was added, and then the resulting mixture was sufficiently mixed by inversion, to prepare Sample 1. Further, a pooled urine (reference sample) containing immobilized erythrocytes was prepared by the method disclosed in Non-patent Document 1.

Using a urine sediment analyzer, AUTION EYE® AI-4510 (manufactured by Arkray, Inc.), the powder particles of NH-RAS06 contained in Sample 1 and particles contained in the reference sample were imaged, to obtain the images of NH-RAS06 and of the immobilized erythrocytes. By observing the images of the particles of NH-RAS06 and the immobilized erythrocytes, it was determined whether or not the form and the particle size of the particles of NH-RAS06 contained in Sample 1 are similar to those of the immobilized erythrocytes contained in the reference sample. The images (photographs) of the particles of NH-RAS06 contained in Sample 1 are shown in FIG. 1, and the images (photographs) of the immobilized erythrocytes contained in the reference sample are shown in FIG. 2. As can be seen from the images shown in FIG. 1 and FIG. 2, both the particles of NH-RAS06 and the immobilized erythrocytes have a spherical form, and the condition of the particles of NH-RAS06 was extremely similar to that of the cytoplasm of the immobilized erythrocytes. Further, 90% or more of the particles of NH-RAS06 contained in Sample 1 were automatically identified as “erythrocytes”.

Using a biological microscope BX-2700TL (manufactured by WRAYMVER Inc.) in HPF mode (magnification: 400 times), the particles of NH-RAS06 contained in Sample 1 and the immobilized erythrocytes contained in the reference sample were observed, to determine whether or not the forms and the particle sizes of both are similar to each other. The images (photographs) of the particles of NH-RAS06 contained in Sample 1 are shown in FIG. 3, and the images (photographs) of the immobilized erythrocytes contained in the reference sample are shown in FIG. 4. As can be seen from the images shown in FIG. 3 and FIG. 4, the form, the particle size and the condition of the particles of NH-RAS06 were extremely similar to those of the immobilized erythrocytes, also in the observation with the biological microscope.

Example 2

The same procedure as in Example 1 was carried out except that Twinone SS-1000 (manufactured by CQV Co., Ltd.) (final concentration: 1.0×10⁻⁴mg/mL), which is golf ball-like amphipathic silicone beads having an average particle size of from 2 μm to 5 μm, was used instead of NH-RAS06 used in Example 1, to prepare Sample 2.

Using AUTION EYE® AI-4510, the bead particles of Twinone SS-1000 contained in Sample 2 were imaged, and the evaluation of Twinone SS-1000 was carried out, in the same manner as in Example 1. The images (photographs) of the particles of Twinone SS-1000 contained in Sample 2 are shown in