Abstract: Disclosed are a leukocyte classification reagent and kit, a classification method, an erythrocyte classification reagent and kit, and an analysis method. Both the leukocyte classification reagent and the erythrocyte classification reagent comprise a fluorescent dye represented by the general formula F. The dye can stain the nucleic acids of leukocytes and erythrocytes, therefore, during blood analysis, the classification and/or counting of leukocytes in a sample can be accurately realized, and the classification and/or counting of erythrocytes in a sample can be accurately realized, in particular the identification and/or counting of RETs. In addition, the types of dyes used in blood cell analysis may also be simplified.