Absolute Counting Beads
Total absolute cell count and percent lymphocyte values are usually obtained using the number of white blood cells and lymphocytes counted on an automated hematology instrument multiplied by the percentage of positivelystained cells measured on a flow cytometer. This Standard (Indirect) Method, however, is associated with wide interlaboratory variation.1-4 Flow-Count Fluorospheres is an efficient alternative to the Standard (Indirect) Method for absolute counts and provides this measure directly using the single platform of flow cytometric immunophenotyping analysis. When identical volumes of a biological specimen and Flow-Count Fluorospheres are present, a ratio of cells in the specimen to fluorospheres is established. The cells of interest and the fluorospheres are then counted on the flow cytometry system.