A procedure employed to verify the presence of a specific substance or condition, typically after a preliminary screening process has indicated a potential positive result. This secondary analysis utilizes a different analytical technique or methodology than the initial screen, aiming to provide a more definitive and reliable identification. For example, in drug testing, an initial immunoassay screen might be followed by gas chromatography-mass spectrometry to confirm the presence and quantity of a particular drug.
The utility of this type of procedure lies in its ability to reduce the incidence of false positives. By employing a more sensitive and specific method, the likelihood of an incorrect positive result is significantly diminished. This is especially critical in contexts where a positive finding carries significant consequences, such as employment decisions, medical diagnoses, or legal proceedings. Historically, the development of these tests has mirrored advancements in analytical chemistry and technology, allowing for increasingly precise and reliable determinations.
