Assay
Overview
 
An assay is a procedure in molecular biology
Molecular biology
Molecular biology is the branch of biology that deals with the molecular basis of biological activity. This field overlaps with other areas of biology and chemistry, particularly genetics and biochemistry...

 for testing or measuring the activity of a drug
Drug
A drug, broadly speaking, is any substance that, when absorbed into the body of a living organism, alters normal bodily function. There is no single, precise definition, as there are different meanings in drug control law, government regulations, medicine, and colloquial usage.In pharmacology, a...

 or biochemical
Biochemistry
Biochemistry, sometimes called biological chemistry, is the study of chemical processes in living organisms, including, but not limited to, living matter. Biochemistry governs all living organisms and living processes...

 in an organism
Organism
In biology, an organism is any contiguous living system . In at least some form, all organisms are capable of response to stimuli, reproduction, growth and development, and maintenance of homoeostasis as a stable whole.An organism may either be unicellular or, as in the case of humans, comprise...

 or organic sample
Sample (material)
In general, a sample is a limited quantity of something which is intended to be similar to and represent a larger amount of that thing. The things could be countable objects such as individual items available as units for sale, or a material not countable as individual items. Samples of countable...

. A quantitative assay may also measure the amount of a substance in a sample. Bioassay
Bioassay
Bioassay , or biological standardization is a type of scientific experiment. Bioassays are typically conducted to measure the effects of a substance on a living organism and are essential in the development of new drugs and in monitoring environmental pollutants...

s and immunoassay
Immunoassay
An immunoassay is a biochemical test that measures the presence or concentration of a substance in solutions that frequently contain a complex mixture of substances. Analytes in biological liquids such as serum or urine are frequently assayed using immunoassay methods...

s are among the many varieties of specialized biochemical assays. Other assays measure processes such as enzyme
Enzyme
Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...

 activity, antigen capture, stem cell
Stem cell
This article is about the cell type. For the medical therapy, see Stem Cell TreatmentsStem cells are biological cells found in all multicellular organisms, that can divide and differentiate into diverse specialized cell types and can self-renew to produce more stem cells...

 activity, and competitive protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

 binding.
A cytotoxicity assay measures how toxic a chemical compound
Chemical compound
A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...

 is to cells
Cell (biology)
The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....

.
  • MTT assay
    MTT assay
    The MTT assay and the MTS assay are colorimetric assays for measuring the activity of enzymes that reduce MTT or close dyes to formazan dyes, giving a purple color. A main application allows to assess the viability and the proliferation of cells...

  • SRB (Sulforhodamine B
    Sulforhodamine b
    Sulforhodamine B or kiton red is a fluorescent dye with uses spanning from laser-induced fluorescence to the quantification of cellular proteins of cultured cells. The red, solid, water-soluble dye is primarily used as a polar tracer.The dye has maximal absorbance at 565 nm light and...

    ) assay

Assays for studying interaction
Interaction
Interaction is a kind of action that occurs as two or more objects have an effect upon one another. The idea of a two-way effect is essential in the concept of interaction, as opposed to a one-way causal effect...

s of proteins with DNA
DNA
Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...

 include:
  • DNase footprinting assay
    DNase footprinting assay
    A DNase footprinting assay is a DNA footprinting technique from molecular biology/biochemistry that detects DNA-protein interaction using the fact that a protein bound to DNA will often protect that DNA from enzymatic cleavage. This makes it possible to locate a protein binding site on a particular...

  • Filter binding assay
    Filter binding assay
    In biochemistry or chemistry, one of the ways to learn about an interaction between two molecules is to determine the binding constant, which is a number that describes the ratio of unbound and bound molecules...

  • Gel shift assay

  • Bicinchoninic acid assay
    Bicinchoninic acid assay
    The bicinchoninic acid assay , also known as the Smith assay, after its inventor, Paul K. Smith at the Pierce Chemical Company, is a biochemical assay for determining the total level of protein in a solution , similar to Lowry protein assay, Bradford protein assay or biuret reagent...

     (BCA assay)
  • Bradford protein assay
    Bradford protein assay
    The Bradford protein assay is a spectroscopic analytical procedure used to measure the concentration of protein in a solution. It is subjective, i.e., dependent on the amino acid composition of the measured protein. The Bradford protein assay was developed by Marion M...

  • Lowry protein assay
    Lowry protein assay
    The Lowry protein assay is a biochemical assay for determining the total level of protein in a solution. The total protein concentration is exhibited by a color change of the sample solution in proportion to protein concentration, which can then be measured using colorimetric techniques. It is...

  • Secretion assay
    Secretion assay
    Secretion assay is a process used in cell biology to identify cells that are secreting a particular protein . It was first developed by Manz et al. in 1995....


A cell-counting assay may determine the number of living cells, the number of dead cells, or the ratio of one cell type to another, such as numerating and typing red
Red blood cell
Red blood cells are the most common type of blood cell and the vertebrate organism's principal means of delivering oxygen to the body tissues via the blood flow through the circulatory system...

 versus different types of white
White blood cell
White blood cells, or leukocytes , are cells of the immune system involved in defending the body against both infectious disease and foreign materials. Five different and diverse types of leukocytes exist, but they are all produced and derived from a multipotent cell in the bone marrow known as a...

 blood cell
Blood cell
A blood cell, also called a hematocyte, is a cell normally found in blood. In mammals, these fall into three general categories:* red blood cells — Erythrocytes* white blood cells — Leukocytes* platelets — Thrombocytes...

s.
Encyclopedia
An assay is a procedure in molecular biology
Molecular biology
Molecular biology is the branch of biology that deals with the molecular basis of biological activity. This field overlaps with other areas of biology and chemistry, particularly genetics and biochemistry...

 for testing or measuring the activity of a drug
Drug
A drug, broadly speaking, is any substance that, when absorbed into the body of a living organism, alters normal bodily function. There is no single, precise definition, as there are different meanings in drug control law, government regulations, medicine, and colloquial usage.In pharmacology, a...

 or biochemical
Biochemistry
Biochemistry, sometimes called biological chemistry, is the study of chemical processes in living organisms, including, but not limited to, living matter. Biochemistry governs all living organisms and living processes...

 in an organism
Organism
In biology, an organism is any contiguous living system . In at least some form, all organisms are capable of response to stimuli, reproduction, growth and development, and maintenance of homoeostasis as a stable whole.An organism may either be unicellular or, as in the case of humans, comprise...

 or organic sample
Sample (material)
In general, a sample is a limited quantity of something which is intended to be similar to and represent a larger amount of that thing. The things could be countable objects such as individual items available as units for sale, or a material not countable as individual items. Samples of countable...

. A quantitative assay may also measure the amount of a substance in a sample. Bioassay
Bioassay
Bioassay , or biological standardization is a type of scientific experiment. Bioassays are typically conducted to measure the effects of a substance on a living organism and are essential in the development of new drugs and in monitoring environmental pollutants...

s and immunoassay
Immunoassay
An immunoassay is a biochemical test that measures the presence or concentration of a substance in solutions that frequently contain a complex mixture of substances. Analytes in biological liquids such as serum or urine are frequently assayed using immunoassay methods...

s are among the many varieties of specialized biochemical assays. Other assays measure processes such as enzyme
Enzyme
Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...

 activity, antigen capture, stem cell
Stem cell
This article is about the cell type. For the medical therapy, see Stem Cell TreatmentsStem cells are biological cells found in all multicellular organisms, that can divide and differentiate into diverse specialized cell types and can self-renew to produce more stem cells...

 activity, and competitive protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

 binding.

Cytotoxicity

A cytotoxicity assay measures how toxic a chemical compound
Chemical compound
A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...

 is to cells
Cell (biology)
The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....

.
  • MTT assay
    MTT assay
    The MTT assay and the MTS assay are colorimetric assays for measuring the activity of enzymes that reduce MTT or close dyes to formazan dyes, giving a purple color. A main application allows to assess the viability and the proliferation of cells...

  • SRB (Sulforhodamine B
    Sulforhodamine b
    Sulforhodamine B or kiton red is a fluorescent dye with uses spanning from laser-induced fluorescence to the quantification of cellular proteins of cultured cells. The red, solid, water-soluble dye is primarily used as a polar tracer.The dye has maximal absorbance at 565 nm light and...

    ) assay

DNA

Assays for studying interaction
Interaction
Interaction is a kind of action that occurs as two or more objects have an effect upon one another. The idea of a two-way effect is essential in the concept of interaction, as opposed to a one-way causal effect...

s of proteins with DNA
DNA
Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...

 include:
  • DNase footprinting assay
    DNase footprinting assay
    A DNase footprinting assay is a DNA footprinting technique from molecular biology/biochemistry that detects DNA-protein interaction using the fact that a protein bound to DNA will often protect that DNA from enzymatic cleavage. This makes it possible to locate a protein binding site on a particular...

  • Filter binding assay
    Filter binding assay
    In biochemistry or chemistry, one of the ways to learn about an interaction between two molecules is to determine the binding constant, which is a number that describes the ratio of unbound and bound molecules...

  • Gel shift assay

Protein

  • Bicinchoninic acid assay
    Bicinchoninic acid assay
    The bicinchoninic acid assay , also known as the Smith assay, after its inventor, Paul K. Smith at the Pierce Chemical Company, is a biochemical assay for determining the total level of protein in a solution , similar to Lowry protein assay, Bradford protein assay or biuret reagent...

     (BCA assay)
  • Bradford protein assay
    Bradford protein assay
    The Bradford protein assay is a spectroscopic analytical procedure used to measure the concentration of protein in a solution. It is subjective, i.e., dependent on the amino acid composition of the measured protein. The Bradford protein assay was developed by Marion M...

  • Lowry protein assay
    Lowry protein assay
    The Lowry protein assay is a biochemical assay for determining the total level of protein in a solution. The total protein concentration is exhibited by a color change of the sample solution in proportion to protein concentration, which can then be measured using colorimetric techniques. It is...

  • Secretion assay
    Secretion assay
    Secretion assay is a process used in cell biology to identify cells that are secreting a particular protein . It was first developed by Manz et al. in 1995....


Cell counting, viability, proliferation or cytotoxicity assays

A cell-counting assay may determine the number of living cells, the number of dead cells, or the ratio of one cell type to another, such as numerating and typing red
Red blood cell
Red blood cells are the most common type of blood cell and the vertebrate organism's principal means of delivering oxygen to the body tissues via the blood flow through the circulatory system...

 versus different types of white
White blood cell
White blood cells, or leukocytes , are cells of the immune system involved in defending the body against both infectious disease and foreign materials. Five different and diverse types of leukocytes exist, but they are all produced and derived from a multipotent cell in the bone marrow known as a...

 blood cell
Blood cell
A blood cell, also called a hematocyte, is a cell normally found in blood. In mammals, these fall into three general categories:* red blood cells — Erythrocytes* white blood cells — Leukocytes* platelets — Thrombocytes...

s. This is measured by different physical methods (light transmission, electric current change). But other methods use biochemical probing cell structure or physiology (stains). Another application is to monitor cell culture
Cell culture
Cell culture is the complex process by which cells are grown under controlled conditions. In practice, the term "cell culture" has come to refer to the culturing of cells derived from singlecellular eukaryotes, especially animal cells. However, there are also cultures of plants, fungi and microbes,...

 (assays
Cell culture assays
In Biomaterials Testing, a cell culture assay is any method which is used to assess the cytotoxicity of a material. This refers to the in vitro assessment of material to determine whether it releases toxic chemicals in sufficient quantities to kill cells either directly or indirectly through the...

 of cell proliferation or cytotoxicity).
  • Cell counting instruments and methods: CASY cell counting technology
    CASY cell counting technology
    CASY technology is an electric field multi-channel cell counting system. It was first marketed by Schärfe System GmbH in 1998. In 2006, Schärfe System was acquired by Innovatis, a company focused on cell culture analysis. CASY utilizes the techniques of electric current exclusion and pulse area...

    , Coulter counter
    Coulter counter
    A Coulter counter is an apparatus for counting and sizing particles suspended in electrolytes. It is used for cells, bacteria, prokaryotic cells and virus particles....

    , Electric cell-substrate impedance sensing
    Electric cell-substrate impedance sensing
    Electric cell-substrate impedance sensing or ECISTM refers to a non-invasive biophysical approach to monitor living animal cells in vitro, i.e...

  • Cell viability assay
    Viability assay
    A viability assay is an assay to determine the ability of cells or tissues to maintain or recover its viability. For example, examining the ratio of potassium to sodium in cells indicates viability because if cells do not have high intracellular potassium and low intracellular sodium:  the...

    s: resazurin method, ATP test
    ATP test
    The ATP test is a process of rapidly measuring actively growing microorganisms through detection of adenosine triphosphate, or ATP.-ATP testing method:...

    , Ethidium homodimer assay
    Ethidium homodimer assay
    An ethidium homodimer assay can be used to detect dead or dying cells. Ethidium homodimer is a membrane-impermeable fluorescent dye which binds to DNA. After a cell sample has been stained with ethidium homodimer, the dead cells may be viewed and counted under a UV-light microscope.When cells die,...

     (detect dead or dying cells), Bacteriological water analysis, Clonogenic assay
    Clonogenic assay
    A clonogenic assay is a microbiology technique for studying the effectiveness of specific agents on the survival and proliferation of cells. It is frequently used in cancer research laboratories to determine the effect of drugs or radiation on proliferating tumor cells as well as for titration of...

    s, ...

Surfactants

  • An MBAS assay
    MBAS assay
    A methylene blue active substances assay, or MBAS assay, is a colorimetric analysis test method that uses methylene blue to detect the presence of anionic surfactants in a sample of water...

     indicates anionic surfactant
    Surfactant
    Surfactants are compounds that lower the surface tension of a liquid, the interfacial tension between two liquids, or that between a liquid and a solid...

    s in water with a bluing reaction.

Other cell assays

Many cell assays have been developed to assess specific parameters or response of cells (biomarkers, cell physiology
Cell biology
Cell biology is a scientific discipline that studies cells – their physiological properties, their structure, the organelles they contain, interactions with their environment, their life cycle, division and death. This is done both on a microscopic and molecular level...

. Techniques used to study cells include :
  • reporter assays using i.e. Luciferase
    Luciferase
    Luciferase is a generic term for the class of oxidative enzymes used in bioluminescence and is distinct from a photoprotein. One famous example is the firefly luciferase from the firefly Photinus pyralis. "Firefly luciferase" as a laboratory reagent usually refers to P...

    , calcium signaling assays using Coelenterazine
    Coelenterazine
    Coelenterazine is the luciferin, the light-emitting molecule, found in many aquatic organisms across seven phyla. It is the substrate in many luciferases and photoproteins including Renilla reniformis luciferase , Gaussia luciferase , aequorin, and obelin.-History:Coelenterazine was simultaneously...

    , CFSE or Calcein
    Calcein
    Calcein, also known as fluorexon, fluorescein complex, is a fluorescent dye with an excitation and emission wavelengths of 495/515 nm, respectively. Calcein also self-quenches even at concentrations below 100mM. It is used as a complexometric indicator for titration of calcium ions with EDTA,...

  • Immunostaining
    Immunostaining
    Immunostaining is a general term in biochemistry that applies to any use of an antibody-based method to detect a specific protein in a sample. The term immunostaining was originally used to refer to the immunohistochemical staining of tissue sections, as first described by Albert Coons in 1941...

     of cells on slides by Microscopy
    Microscopy
    Microscopy is the technical field of using microscopes to view samples and objects that cannot be seen with the unaided eye...

     (ImmunoHistoChemistry or Fluorescence), on microplates by photometry
    Photometry (optics)
    Photometry is the science of the measurement of light, in terms of its perceived brightness to the human eye. It is distinct from radiometry, which is the science of measurement of radiant energy in terms of absolute power; rather, in photometry, the radiant power at each wavelength is weighted by...

     including the ELISPOT
    ELISPOT
    The Enzyme-linked immunosorbent spot assay is a common method for monitoring immune responses in humans and animals. It was developed by Cecil Czerkinsky in 1983....

     (and its variant FluoroSpot
    FluoroSpot
    The FluoroSpot assay is a modification of the ELISPOT assay. ELISPOT usually measures the cellular secretion of one cytokine in each well by the use of an enzyme-labeled anti-cytokine antibody. FluoroSpot measures the secretion of several cytokines in each well by the use of fluorescent...

    ) to enumerate B-Cells or antigen-specific cells, in solution by Flow cytometry
    Flow cytometry
    Flow cytometry is a technique for counting and examining microscopic particles, such as cells and chromosomes, by suspending them in a stream of fluid and passing them by an electronic detection apparatus. It allows simultaneous multiparametric analysis of the physical and/or chemical...

  • Immunostaining
    Immunostaining
    Immunostaining is a general term in biochemistry that applies to any use of an antibody-based method to detect a specific protein in a sample. The term immunostaining was originally used to refer to the immunohistochemical staining of tissue sections, as first described by Albert Coons in 1941...

     of cells on slides by Microscopy
    Microscopy
    Microscopy is the technical field of using microscopes to view samples and objects that cannot be seen with the unaided eye...

    , on microplates by photometry
  • Molecular biology
    Molecular biology
    Molecular biology is the branch of biology that deals with the molecular basis of biological activity. This field overlaps with other areas of biology and chemistry, particularly genetics and biochemistry...

     techniques such as DNA microarray
    DNA microarray
    A DNA microarray is a collection of microscopic DNA spots attached to a solid surface. Scientists use DNA microarrays to measure the expression levels of large numbers of genes simultaneously or to genotype multiple regions of a genome...

    s, in situ hybridization
    In situ hybridization
    In situ hybridization is a type of hybridization that uses a labeled complementary DNA or RNA strand to localize a specific DNA or RNA sequence in a portion or section of tissue , or, if the tissue is small enough , in the entire tissue...

    , combined to PCR, Computational genomics
    Computational genomics
    Computational genomics refers to the use of computational analysis to decipher biology from genome sequences and related data , including both DNA and RNA sequence as well as other "post-genomic" data...

    , and Transfection
    Transfection
    Transfection is the process of deliberately introducing nucleic acids into cells. The term is used notably for non-viral methods in eukaryotic cells...

    ; Cell fractionation
    Cell fractionation
    Cell fractionation is the separation of homogeneous sets, usually organelles, from a heterogeneous population of cells.-Steps:There are three principal steps involved:#Disruption of cells and liberation of organelles.#Macro Filtration...

     or Immunoprecipitation
    Immunoprecipitation
    Immunoprecipitation is the technique of precipitating a protein antigen out of solution using an antibody that specifically binds to that particular protein. This process can be used to isolate and concentrate a particular protein from a sample containing many thousands of different proteins...

  • Migration assays, Chemotaxis assay
    Chemotaxis assay
    Chemotaxis assays are experimental tools for evaluation of chemotactic ability of prokaryotic or eukaryotic cells.A wide variety of techniques are known and applied for such reason...

  • Secretion assay
    Secretion assay
    Secretion assay is a process used in cell biology to identify cells that are secreting a particular protein . It was first developed by Manz et al. in 1995....

    s
  • Apoptosis
    Apoptosis
    Apoptosis is the process of programmed cell death that may occur in multicellular organisms. Biochemical events lead to characteristic cell changes and death. These changes include blebbing, cell shrinkage, nuclear fragmentation, chromatin condensation, and chromosomal DNA fragmentation...

     assays such as Single Cell Gel Electrophoresis (Comet assay - Apoptosis DNA fragmentation
    Apoptosis DNA Fragmentation
    Apoptosis DNA fragmentation is a key feature of programmed cell death and also occurs in certain stages of necrosis. Apoptosis is characterized by the activation of endogenous endonucleases with subsequent cleavage of chromatin DNA into internucleosomal fragments of 180 BP and multiples thereof.DNA...

    ), Annexin V
  • Chemosensitivity assay
    Chemosensitivity assay
    A chemosensitivity assay is a laboratory test that measures the number of tumor cells that are killed by chemotherapy. The test is done after the tumor cells are removed from the body...

     measures the number of tumor cells that are killed by a cancer drug
  • Tetramer assay
    Tetramer assay
    A tetramer assay is used to detect the presence of antigen specific T-cells. In order for a T-cell to detect the peptide to which it is specific, it must both recognize the peptide AND the MHC complex at the surface of a cell it comes into contact with...

     detect the presence of antigen specific T-cells
  • Gentamicin protection assay
    Gentamicin protection assay
    The gentamicin protection assay or survival assay or invasion assay is a method used in microbiology. It is used to quantify the ability of pathogenic bacteria to invade eukaryotic cells....

     or survival assay or invasion assay to asses ability of pathogens (bacteria) to invade eukaryotic cells

Virology

The HPCE-based viral titer assay
HPCE-based viral titer assay
HPCE is widely used in the analysis of biomolecules. Recently, a further application, to titer baculovirus, has been developed using HPCE technology and a proprietary buffer system belonging to the UK company deltaDOT...

 uses a proprietary, high-performance capillary electrophoresis
Capillary electrophoresis
Capillary electrophoresis , also known as capillary zone electrophoresis , can be used to separate ionic species by their charge and frictional forces and hydrodynamic radius. In traditional electrophoresis, electrically charged analytes move in a conductive liquid medium under the influence of an...

 system to determine baculovirus
Baculovirus
The baculoviruses are a family of large rod-shaped viruses that can be divided to two genera: nucleopolyhedroviruses and granuloviruses . While GVs contain only one nucleocapsid per envelope, NPVs contain either single or multiple nucleocapsids per envelope. The enveloped virions are further...

 titer
Titer
A titer is a way of expressing concentration. Titer testing employs serial dilution to obtain approximate quantitative information from an analytical procedure that inherently only evaluates as positive or negative. The titer corresponds to the highest dilution factor that still yields a positive...

.

The Trofile assay
Trofile assay
The Trofile assay is a blood test that identifies the tropism of a patient's HIV.A molecular assay, Trofile was developed by Monogram Biosciences for use in HIV treatment. The assay's purpose is to identify the tropism of an individual patient's HIV strain – R5, X4, or a combination of these known...

 is used to determine HIV tropism
HIV tropism
HIV tropism refers to the cell type that the human immunodeficiency virus infects and replicates in. HIV tropism of a patient's virus is measured by the Trofile assay....

.

The viral plaque assay is to calculate the number of virus
Virus
A virus is a small infectious agent that can replicate only inside the living cells of organisms. Viruses infect all types of organisms, from animals and plants to bacteria and archaea...

es present in a sample. In this technique the number of viral plaque
Viral plaque
A viral plaque is a visible structure formed within a cell culture, such as bacterial cultures within some nutrient medium . The bacteriophage viruses replicate and spread, thus generating regions of cell destructions known as plaques....

s formed by a viral inoculum is counted, from which the actual virus concentration can be determined.

Cellular secretions

A wide range of cellular secretions (say, a specific antibody
Antibody
An antibody, also known as an immunoglobulin, is a large Y-shaped protein used by the immune system to identify and neutralize foreign objects such as bacteria and viruses. The antibody recognizes a unique part of the foreign target, termed an antigen...

 or cytokine
Cytokine
Cytokines are small cell-signaling protein molecules that are secreted by the glial cells of the nervous system and by numerous cells of the immune system and are a category of signaling molecules used extensively in intercellular communication...

) can be detected using the ELISA
ELISA
Enzyme-linked immunosorbent assay , is a popular format of a "wet-lab" type analytic biochemistry assay that uses one sub-type of heterogeneous, solid-phase enzyme immunoassay to detect the presence of a substance in a liquid sample."Wet lab" analytic biochemistry assays involves detection of an...

 technique. The number of cells which secrete those particular substances can be determined using a related technique, the ELISPOT
ELISPOT
The Enzyme-linked immunosorbent spot assay is a common method for monitoring immune responses in humans and animals. It was developed by Cecil Czerkinsky in 1983....

 assay.

Drugs

  • Testing for Illegal Drugs
    Drug test
    A drug test is a technical analysis of a biological specimen – for example urine, hair, blood, sweat, or oral fluid / saliva – to determine the presence or absence of specified parent drugs or their metabolites...

  • Radioligand binding assay

See also

  • Analytical chemistry
    Analytical chemistry
    Analytical chemistry is the study of the separation, identification, and quantification of the chemical components of natural and artificial materials. Qualitative analysis gives an indication of the identity of the chemical species in the sample and quantitative analysis determines the amount of...

  • MELISA
    MELISA
    A MELISA test is a blood test that detects Type-IV allergy to metals, chemicals, environmental toxins and molds from one single blood sample. It can also identify active Lyme disease . The test does not measure toxicity-that is to say, it will not measure the amounts of a harmful substance in the...

  • Multiplex (assay)
    Multiplex (assay)
    A multiplex assay is a type of laboratory procedure that simultaneously measures multiple analytes in a single assay. It is distinguished from procedures that measure one or a few analytes at a time...

  • Pharmaceutical chemistry
  • Titration
    Titration
    Titration, also known as titrimetry, is a common laboratory method of quantitative chemical analysis that is used to determine the unknown concentration of an identified analyte. Because volume measurements play a key role in titration, it is also known as volumetric analysis. A reagent, called the...

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