Editing Assay (section)

{{Short description|Measure the amount of a target entity}}
{{About|assays in biology|assays of metals|metallurgical assay|the French commune|Assay, Indre-et-Loire}}
{{More citations needed|date=August 2016}}

An '''assay''' is an investigative (analytic) procedure in [[laboratory medicine]], [[mining]], [[pharmacology]], [[environmental biology]] and [[molecular biology]] for qualitatively assessing or quantitatively measuring the presence, amount, or functional activity of a target entity. The measured entity is often called the '''analyte''', the '''measurand''', or the '''target''' of the assay. The analyte can be a [[drug]], [[Biochemistry|biochemical substance]], [[chemical element]] or [[chemical compound|compound]], or [[Cell (biology)|cell]] in an [[organism]] or organic [[Sample (material)|sample]].<ref>{{cite book|title=The American heritage dictionary of the English language|date=2006|publisher=Houghton Mifflin|location=Boston, MA|isbn=9780618701735|edition=4th}}</ref><ref>{{cite book|last1=Abate|first1=Frank|editor1-last=J. Jewell|editor1-first=Elizabeth|title=The new Oxford American dictionary|date=2001|publisher=Oxford University Press|location=Oxford|isbn=9780195112276|edition=2nd|url-access=registration|url=https://archive.org/details/newoxfordamerica0000unse}}</ref> An assay usually aims to measure an analyte's [[Intensive and extensive properties|intensive property]] and express it in the relevant [[Unit of measurement|measurement unit]] (e.g. [[molarity]], [[density]], functional activity in enzyme international units, degree of effect in comparison to a standard, etc.).

If the assay involves [[exogenous]] reactants (the [[reagent]]s), then their quantities are kept fixed (or in excess) so that the quantity and quality of the target are the only limiting factors. The difference in the assay outcome is used to [[Deductive reasoning|deduce]] the unknown quality or quantity of the target in question. Some assays (e.g., biochemical assays) may be similar to [[Analytical chemistry|chemical analysis]] and [[titration]]. However, assays typically involve [[Organic matter|biological material]] or phenomena that are intrinsically more complex in composition or behavior, or both. Thus, reading of an assay may be [[Signal-to-noise ratio|noisy]] and involve greater difficulties in interpretation than an accurate chemical titration. On the other hand, older generation qualitative assays, especially [[bioassay]]s, may be much more gross and less quantitative (e.g., counting death or dysfunction of an organism or cells in a population, or some descriptive change in some body part of a group of animals).

Assays have become a routine part of modern [[Health technology|medical]], [[Environmental technology|environmental]], [[Pharmaceutics|pharmaceutical]], and [[Forensic science|forensic technology]]. Other businesses may also employ them at the [[Industrial technology|industrial]], curbside, or field levels.  Assays in high commercial demand have been well investigated in [[research and development]] sectors of professional industries. They have also undergone generations of development and sophistication. In some cases, they are protected by intellectual property regulations such as [[patent]]s granted for inventions. Such industrial-scale assays are often performed in well-equipped [[Laboratory|laboratories]] and with automated organization of the procedure, from ordering an assay to pre-analytic sample processing (sample collection, necessary manipulations e.g. [[Centrifuge|spinning for separation]], [[sample_(material)#Aliquot_part|aliquoting]] if necessary, storage, retrieval, [[Pipette|pipetting]], [[Suction|aspiration]], etc.). Analytes are generally tested in high-[[throughput]] [[autoanalyzer]]s, and the results are verified and automatically returned to ordering service providers and [[End user|end-users]]. These are made possible through the use of an advanced [[laboratory informatics system]] that [[Interface (computing)|interfaces]] with multiple [[computer terminal]]s with end-users, central [[Server (computing)|servers]], the physical autoanalyzer instruments, and other automata.{{Clarify|reason=I assume "automata" doesn't mean "robots" in this context, so what does it mean?|date=October 2021}}