Assay is a research area that involves the quantitative determination or measurement of a substance or property in a sample, typically using specialized techniques or methods. Assays can be used to detect and quantify a wide range of analytes, such as proteins, enzymes, DNA, hormones, drugs, and chemicals. They are commonly used in biological, pharmaceutical, and environmental research to investigate the presence, concentration, or activity of specific substances. Assays can be classified into various types, including biochemical assays, immunoassays, cell-based assays, and nucleic acid assays, among others. These techniques are essential for studying biological processes, disease mechanisms, drug development, and environmental monitoring.