What are QBC blood analyzers?

In terms of blood analysis, "QBC" stands for "qualitative buffy coat". The buffy coat of a centrifuged blood sample contains the white blood cells of the blood, so a qualitative (numerical) analysis of the buffy coat is analogous to a differential white blood cell count in an uncentrifuged blood sample. A QBC blood analyzer is simply a machine that automatically performs these counts and presents the results to the physician or veterinarian.