Fluorescent Immunoassay is a laboratory technique used to detect and quantify specific proteins or antigens in a sample. It utilizes antibodies that are tagged with fluorescent dyes, allowing for visualization under a fluorescence microscope. When the antibodies bind to their target, the resulting complex emits light, indicating the presence and amount of the substance being tested. This method is widely used in clinical diagnostics, research, and drug development due to its sensitivity and specificity. Fluorescent Immunoassays can be applied to various samples, including blood, urine, and tissue, making them valuable tools in medical and scientific fields.