Used in semen analysis to assess sperm concentration and viability. The solution allows sperm cells to be counted accurately under a microscope using a hemocytometer. Trypan blue dye stains dead or membrane-damaged sperm cells, distinguishing them from live ones, which remain unstained. This helps in evaluating male fertility by providing both total sperm count and percentage of viable sperm. Commonly used in clinical labs, fertility clinics, and research settings involving reproductive health.