From Wikipedia,
the free encyclopedia.
- For
other uses of this term, see
Assay (disambiguation).
An assay is a procedure
where the
concentration of a component
part of a
mixture is determined.
There are numerous applications
of an assay, such as an antigen
capture assay, bioassay,
competitive protein binding
assay, four-point assay,
immunoassay,
microbiological assay, stem
cell assay, and many others.
In the laboratory
Assays are regularly utilized
in scientific research
laboratories.
DNA
Assays for studying
interactions of
protein with
DNA include:
Protein
Cytotoxicity
Assays for studying how toxic a
compound is to cells:
Viruses
The number of
viruses present in a sample
can be determined using a
viral plaque assay. This
technique requires counting the
number of plaques formed by a
virus sample, from which the
actual virus concentration can be
determined.
Cellular secretions
A wide range of cellular
secretions (say, a specific
antibody or
cytokine) can be detected
using the
ELISA technique. The number of
cells which secrete those
particular substances can be
determined using a related
technique, the
ELISPOT assay.
Drugs
Illegal drug testing
Environmental contaminants
Coins
An assayer is often
assigned to each
mint to determine and assure
that all
coins produced there have the
correct
content or
purity of each
metal in them. This is
particularly important with
gold and
silver coins.
Precious metals
Precious metals,
platinum, gold and silver,
used in
jewellery,
silverware and other items,
are assayed to test the purity of
the metal.
This is done in the UK by an
Assay Office. Once an item has
been assayed, it is usually
hallmarked to the relevant
standard.
