reagent
Meaning of reagent: A reagent is a substance used in a laboratory reaction to detect, measure, or produce another substance, forming the basis of many diagnostic tests.
Definition of reagent
A reagent is a substance used to carry out a chemical reaction in a laboratory setting, typically to detect, measure, or help produce another substance. Reagents are chosen for how reliably and specifically they react with a particular target, which allows their reaction to serve as the basis for a test.
In clinical laboratory testing, reagents are used to identify or quantify substances such as glucose, cholesterol, or specific proteins in a blood sample, and to determine blood type by testing how a sample reacts with a known reagent designed for that purpose. Reagents are also used in histology to stain tissue samples for examination under a microscope.
A test's reliability depends heavily on the quality and proper handling of its reagents, since a reagent that has degraded or been contaminated can produce an inaccurate result even when the rest of the testing process is performed correctly.
Used in a sentence
The laboratory added a reagent to the blood sample to measure the concentration of glucose present.
Good to know
A laboratory result depends on the reagent used reacting predictably with the target substance, so a degraded or contaminated reagent can produce an inaccurate result even when the rest of the test is performed correctly.
Word origin
Where “reagent” comes from
Formed from Latin re-, meaning again, and agere, meaning to act, describing a substance that acts upon another.