Assay

An assay is an investigative procedure in laboratory medicine, pharmacology, environmental biology, and molecular biology for qualitatively assessing or quantitatively measuring the presence, amount, or functional activity of a target entity (the analyte). The analyte can be a drug, a biochemical substance, or a cell in an organism or organic sample.

Types of Assays

Assays can be broadly categorized into several types based on their purpose and methodology:

Biochemical Assays

Biochemical assays are used to measure the concentration or activity of a biochemical substance. These include:

• Enzyme-linked immunosorbent assay (ELISA)
• Radioimmunoassay (RIA)
• Western blot

Cell-based Assays

Cell-based assays are used to measure cellular responses to stimuli. These include:

• Cytotoxicity assay
• Proliferation assay
• Reporter gene assay

Molecular Assays

Molecular assays are used to detect specific sequences in DNA or RNA. These include:

• Polymerase chain reaction (PCR)
• Quantitative PCR (qPCR)
• Next-generation sequencing (NGS)

Environmental Assays

Environmental assays are used to detect and quantify pollutants or other environmental factors. These include:

• Bioassay
• Chemical assay

Applications

Assays are crucial in various fields:

• In medicine, assays are used for diagnosis, prognosis, and monitoring of diseases.
• In pharmacology, they are used for drug discovery and drug development.
• In environmental science, assays help in monitoring and managing environmental pollutants.

Procedure

The procedure of an assay typically involves the following steps: 1. Sample collection 2. Sample preparation 3. Reaction setup 4. Detection and measurement 5. Data analysis

Related Pages

• Enzyme-linked immunosorbent assay
• Polymerase chain reaction
• Western blot
• Bioassay
• Drug discovery
• Environmental monitoring