In pathology, a reagent is a substance or compound that is added to a biological specimen, such as blood or urine, to produce a chemical reaction or to detect the presence of a particular substance or disease marker.
Reagents are essential for laboratory tests and diagnostic procedures, and they can be used to identify and measure various components of a biological sample, such as proteins, enzymes, hormones, and genetic material. Examples of common reagents used in pathology include antibodies, enzymes, dyes, stains, and buffers.