Patients with hypersensitivity reactions, sometimes as a result of medications, may have eosinophils in their urine. Hansel stain is specific for eosinophils and will stain the cytoplasmic granules red, distinguishing these cells from neutrophils. The cells indicated by the arrows in this Hansel-stained microscopic field are eosinophils.
For distinguishing WBC's in urine, some labs may have protocols that direct the laboratory scientist or technician to prepare a cytospin slide from the urine sediment. Once the slide has been made, it can be stained with a Romanowsky stain such as Wright stain or Wright-Giemsa stain.