Editing Antibody (section)

===Disease diagnosis===
Detection of particular antibodies is a very common form of medical [[medical diagnosis|diagnostics]], and applications such as [[serology]] depend on these methods.<ref>{{cite web |url=http://www.immunospot.eu/elisa-animation.html |title=Animated depictions of how antibodies are used in ELISA assays |access-date=8 May 2007 |website=Cellular Technology Ltd.—Europe |archive-url=https://web.archive.org/web/20110614091640/http://www.elispot-analyzers.de/english/elisa-animation.html |archive-date=14 June 2011 |url-status=dead}}</ref> For example, in biochemical assays for disease diagnosis,<ref>{{cite web |url=http://www.immunospot.eu/elispot-animation.html |title=Animated depictions of how antibodies are used in ELISPOT assays |access-date=8 May 2007 |website=Cellular Technology Ltd.—Europe |archive-url=https://web.archive.org/web/20110516142529/http://www.elispot-analyzers.de/english/elispot-animation.html |archive-date=16 May 2011 |url-status=dead}}</ref> a [[titer]] of antibodies directed against [[Epstein-Barr virus]] or [[Lyme disease]] is estimated from the blood. If those antibodies are not present, either the person is not infected or the infection occurred a ''very'' long time ago, and the B cells generating these specific antibodies have naturally decayed.{{cn|date=July 2024}}

In [[clinical immunology]], levels of individual classes of immunoglobulins are measured by [[nephelometry]] (or [[turbidimetry]]) to characterize the antibody profile of patient.<ref>{{cite journal |author=Stern P |title=Current possibilities of turbidimetry and nephelometry |journal=Klin Biochem Metab |volume=14 |issue=3 |pages=146–151 |year=2006 |url=http://www.clsjep.cz/odkazy/kbm0603-146.pdf |archive-url=https://web.archive.org/web/20080410032918/http://www.clsjep.cz/odkazy/kbm0603-146.pdf |archive-date=10 April 2008 |url-status=dead}}</ref> Elevations in different classes of immunoglobulins are sometimes useful in determining the cause of [[liver]] damage in patients for whom the diagnosis is unclear.<ref name=Rhoades/> For example, IgM levels are often elevated in patients with [[primary biliary cirrhosis]], whereas IgA deposition along hepatic sinusoids can suggest [[alcoholic liver disease]].<ref>{{Cite journal |last1=Martin |first1=David M. |last2=Vroon |first2=David H. |last3=Nasrallah |first3=Salah M. |date=June 1984 |title=Value of serum immunoglobulins in the diagnosis of liver disease |url=https://onlinelibrary.wiley.com/doi/10.1111/j.1600-0676.1984.tb00930.x |journal=Liver |language=en |volume=4 |issue=3 |pages=214–218 |doi=10.1111/j.1600-0676.1984.tb00930.x |pmid=6748875 |issn=0106-9543}}</ref><ref>{{Cite journal |last1=Van De Wiel |first1=Albert |last2=Delacroix |first2=Dominique L. |last3=Van Hattum |first3=Jan |last4=Schuurman |first4=Henk-Jan |last5=Kater |first5=Louis |date=January 1987 |title=Characteristics of serum IgA and liver IgA deposits in alcoholic liver disease |url=https://journals.lww.com/01515467-198701000-00019 |journal=Hepatology |language=en |volume=7 |issue=1 |pages=95–99 |doi=10.1002/hep.1840070120 |pmid=3542782 |issn=0270-9139}}</ref>

[[Autoimmune disorder]]s can often be traced to antibodies that bind the body's own [[epitope]]s; many can be detected through [[blood test]]s. Antibodies directed against [[red blood cell]] surface antigens in immune mediated [[hemolytic anemia]] are detected with the [[Coombs test]].<ref name=Dean>{{cite book | vauthors = Dean L |title= Blood Groups and Red Cell Antigens| year= 2005|publisher=National Library of Medicine (US) |location=NCBI Bethesda (MD)|chapter= Chapter 4: Hemolytic disease of the newborn |chapter-url= https://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=rbcantigen.chapter.ch4}}</ref> The Coombs test is also used for antibody screening in [[blood transfusion]] preparation and also for antibody screening in [[antenatal]] women.<ref name=Dean/>

Practically, several immunodiagnostic methods based on detection of complex antigen-antibody are used to diagnose infectious diseases, for example [[ELISA]], [[immunofluorescence]], [[Western blot]], [[immunodiffusion]], [[immunoelectrophoresis]], and [[magnetic immunoassay]].<ref>{{cite journal |last1=Sullivan |first1=Mark V |last2=Stockburn |first2=William J |last3=Hawes |first3=Philippa C |last4=Mercer |first4=Tim |last5=Reddy |first5=Subrayal M |title=Green synthesis as a simple and rapid route to protein modified magnetic nanoparticles for use in the development of a fluorometric molecularly imprinted polymer-based assay for detection of myoglobin |journal=Nanotechnology |date=26 February 2021 |volume=32 |issue=9 |pages=095502 |doi=10.1088/1361-6528/abce2d|pmid=33242844 |bibcode=2021Nanot..32i5502S |doi-access=free |pmc=8314874 }}</ref> 

Over-the-counter home pregnancy tests rely on [[human chorionic gonadotropin]] (hCG)-directed antibodies.<ref>{{Cite journal |last1=Gnoth |first1=C. |last2=Johnson |first2=S. |date=2014-08-01 |title=Strips of Hope: Accuracy of Home Pregnancy Tests and New Developments |journal=Geburtshilfe und Frauenheilkunde |language=de |volume=74 |issue=7 |pages=661–669 |doi=10.1055/s-0034-1368589 |issn=0016-5751 |pmc=4119102 |pmid=25100881}}</ref>

New dioxaborolane chemistry enables radioactive [[fluoride]] ([[Fluorine-18|<sup>18</sup>F]]) labeling of antibodies, which allows for [[positron emission tomography]] (PET) imaging of [[cancer]].<ref>{{cite journal | vauthors = Rodriguez EA, Wang Y, Crisp JL, Vera DR, Tsien RY, Ting R | title = New Dioxaborolane Chemistry Enables [(18)F]-Positron-Emitting, Fluorescent [(18)F]-Multimodality Biomolecule Generation from the Solid Phase | language = EN | journal = Bioconjugate Chemistry | volume = 27 | issue = 5 | pages = 1390–1399 | date = May 2016 | pmid = 27064381 | pmc = 4916912 | doi = 10.1021/acs.bioconjchem.6b00164 }}</ref>