Diagnostic assays are tests used to detect and measure specific substances in biological samples, such as blood or urine. These assays help identify diseases, monitor health conditions, and guide treatment decisions. Common types include enzyme-linked immunosorbent assays (ELISA), polymerase chain reaction (PCR), and rapid antigen tests. The results from diagnostic assays can provide crucial information about a patient's health status. They are essential tools in clinical laboratories and are widely used in various fields, including infectious disease, oncology, and genetic testing. Accurate and timely results can significantly impact patient care and outcomes.