The process of testing is essential for various industries, including pharmaceuticals, chemicals, and materials. Testing agents are substances used to help obtain accurate and reliable results during the testing process. Synonyms for testing agents include reagents, diagnostic tools, detection systems, assay kits, and probes. Reagents are chemicals used in chemical analysis and are used to identify or quantify the presence of other substances. Diagnostic tools are instruments or devices used for identifying or diagnosing disease or conditions. Detection systems are methods utilized to detect or confirm the presence of specific substances. Assay kits are test kits that measure the activity or concentration of a substance in a sample, and probes are instruments used to search and identify substances in samples.