UroVysion is a fluorescence in situ hybridization assay that was developed for the detection of bladder cancer in urine specimens. It consists of fluorescently labeled DNA probes to the pericentromeric regions of chromosomes 3 (red), 7 (green), and 17 (aqua) and to the 9p21 band (gold) location of the P16 tumor suppressor gene. The UroVysion assay works by detecting urinary cells that have chromosomal abnormalities consistent with a diagnosis of bladder cancer. Studies have shown that UroVysion is more sensitive than urine cytology for the detection of all stages and grades of bladder cancer. UroVysion is Food and Drug Administration-approved for the detection of recurrent bladder cancer in voided urine specimens from patients with a history of bladder cancer and for the detection of bladder cancer in voided urine specimens from patients with gross or microscopic hematuria, but no previous history of bladder cancer. Recent studies also suggest that UroVysion may be useful for assessing superficial bladder cancer patients' response to bacillus Calmette-Guerin therapy and in detecting upper tract urothelial carcinoma.