Used in clinical andrology and fertility laboratories to assess the functional integrity of sperm membranes. This solution helps determine sperm viability by exposing sperm to a hypo-osmotic environment, causing water to enter live sperm with intact membranes, which then exhibit characteristic tail swelling. This reaction allows technicians to differentiate live sperm from dead ones under a microscope, especially useful when sperm motility is low. The test supports accurate diagnosis of male infertility and is commonly used before assisted reproductive procedures like IVF or ICSI to ensure viable sperm are selected for injection. It is also employed in sperm bank quality control and post-thaw evaluation of cryopreserved sperm samples.