View source for Exudate

{{short description|Fluid emitted through pores or a wound}}
{{for|another meaning|Surfactant leaching}}
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| caption1          = Exudate from a wound on a human finger
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An '''exudate''' is a fluid released by an [[organism]] through pores or a wound, a process known as '''exuding''' or '''exudation'''.<ref>{{cite web|website=The Free Dictionary - Medical|title=exudate|url=http://medical-dictionary.thefreedictionary.com/exudate|access-date=5 August 2014}}</ref> 
''Exudate'' is derived from ''exude'' 'to ooze'<ref>{{cite web |url=http://www.merriam-webster.com/dictionary/exude |title="Exude" Merriam-Webster Online Dictionary |access-date=2008-07-04 |year=2008 |publisher=[[Merriam Webster]]}}</ref> from [[Latin language|Latin]] {{Lang|la|exsūdāre}} 'to (ooze out) sweat' (''{{Lang|la|ex-}}'' 'out' and ''{{Lang|la|sūdāre}}'' 'to sweat').<ref>{{cite book |title=Chambers Dictionary of Etymology |editor=Robert K. Barnhart |year=1988 |publisher=Chambers Harrap Publishers |location=New York |isbn=0-550-14230-4 |page=363}}</ref>

==Medicine==

An exudate is any [[fluid]] that filters from the [[circulatory system]] into [[lesion]]s or areas of [[inflammation]]. It can be a pus-like or clear fluid. When an injury occurs, leaving skin exposed, it leaks out of the blood vessels and into nearby tissues. The fluid is composed of [[serum (blood)|serum]], [[fibrin]], and [[White blood cell|leukocytes]]. Exudate may ooze from cuts or from areas of infection or inflammation.<ref>{{cite web|url=https://www.nlm.nih.gov/medlineplus/ency/article/002357.htm|title=Exudate|publisher=MedlinePlus}}</ref>   Although blood itself is not an exudate,<ref>{{cite web |title=Medical Definition of Exudate |url=https://www.rxlist.com/exudate/definition.htm |website=RxList |access-date=28 June 2025 |language=en}}</ref> some types of exudates contain blood cells.<ref>{{cite web |author1=Carole Jakucs |author2=Zelda Meeker |title=Exudate: What the Types and Quantities Tell You |url=https://blog.wcei.net/types-of-exudate-wound-and-what-quantities-tell-you |website=WCEI |publisher=Wound Care Education Institute |access-date=28 June 2025 |date=26 January 2023}}</ref>

===Types===
{{Transudate vs. exudate}}
* Purulent or suppurative exudate consists of plasma with both active and dead [[neutrophils]], [[fibrinogen]], and [[necrotic]] [[parenchymal cells]]. This kind of exudate is consistent with more severe infections, and is commonly referred to as [[pus]].
* Fibrinous exudate is composed mainly of [[fibrinogen]] and [[fibrin]]. It is characteristic of [[Rheumatic fever|rheumatic carditis]], but is seen in all severe injuries such as [[strep throat]] and [[bacterial pneumonia]]. Fibrinous inflammation is often difficult to resolve due to blood vessels growing into the exudate and filling space that was occupied by fibrin. Often, large amounts of antibiotics are necessary for resolution.
* [[Catarrh|Catarrhal exudate]] is seen in the nose and throat and is characterized by a high content of mucus.
* Serous exudate (sometimes classified as serous [[transudate]]) is usually seen in mild inflammation, with relatively low protein.<ref>Robbins Basic Pathology 7th ed</ref> Its consistency resembles that of serum, and can usually be seen in certain disease states like [[tuberculosis]]. (See below for difference between transudate and exudate)
* Malignant (or cancerous) pleural effusion is effusion where [[cancer cell]]s are present.<ref>[http://lungcancer.about.com/od/treatmentoflungcancer/a/malignanteffusion.htm About.com > Malignant Pleural Effusion] {{Webarchive|url=https://web.archive.org/web/20120226002755/http://lungcancer.about.com/od/treatmentoflungcancer/a/malignanteffusion.htm |date=2012-02-26 }} By Lynne Eldridge MD. Updated March 27, 2010</ref> It is usually classified as exudate.

Types of exudates: serous, serosanguineous, sanguineous, hemorrhaging and purulent drainage.
*Serous: Clear straw colored liquid that drains from the wound. This is a normal part of the healing process.
*Serosanguineous: Small amount of blood is present in the drainage; it is pink in color due to the presence of red blood cells mixed with serous drainage. This is a normal part of the healing process.
*Sanguineous: This type of drainage contains red blood due to trauma of blood vessels, this may occur while cleaning the wound. Sanguineous drainage is abnormal.
*Hemorrhaging: This type of drainage contains frank blood from a leaking blood vessel. This will require emergency treatment to control the bleed. This type of drainage is abnormal.
*Purulent drainage: This type of drainage is malodorous and can be yellow, gray, or greenish in color. This is an indication of an infection.

===Exudates vs. transudates===

There is an important distinction between [[transudates]] and exudates. Transudates are caused by disturbances of [[hydrostatic pressure|hydrostatic]] or [[colloid osmotic pressure]], not by inflammation. They have a low protein content in comparison to exudates. Medical distinction between transudates and exudates is through the measurement of the [[specific gravity]] of extracted fluid. Specific gravity is used to measure the protein content of the fluid. The higher the specific gravity, the greater the likelihood of [[capillary]] [[Vascular permeability|permeability]] changes in relation to [[body cavity|body cavities]]. For example, the specific gravity of the transudate is usually less than 1.012 and a protein content of less than 2&nbsp;g/100&nbsp;mL (2&nbsp;g%). [[Rivalta test]] may be used to differentiate an exudate from a transudate.
It is not clear if there is a distinction in the difference of transudates and exudates in plants.

==Plant exudates==
Plant exudates include [[Plant saps|saps]], [[Natural gum|gums]], [[latex]], and [[resin]]. Sometimes [[nectar]] is considered an exudate.<ref>{{cite book|title=The Evolution of Exudativory in Primates / Nutritional and Digestive Challenges to Being a Gum-feeding Primate|year=2010|publisher=Springer|url=https://books.google.com/books?id=YdQg-YoghHEC&pg=PA28|author=Power, Michael L.|editor1=Anne M. Burrows |editor2=Leanne T. Nash |access-date=2 October 2012|page=28|isbn=9781441966612}}</ref> Plant seeds exudate a variety of molecules into the [[spermosphere]],<ref name="Schiltz">{{cite journal |last1=Schiltz |first1=S |last2=Gaillard |first2=I |last3=Pawlicki-Jullian |first3=N |last4=Thiombiano |first4=B |last5=Mesnard |first5=F |last6=Gontier |first6=E |title=A review: what is the spermosphere and how can it be studied? |journal=Journal of Applied Microbiology |date=December 2015 |volume=119 |issue=6 |pages=1467–81 |doi=10.1111/jam.12946 |pmid=26332271|s2cid=42515027 |doi-access= }}</ref> and [[Root mucilage|roots exudate]] into the [[rhizosphere]]; these exudates include acids, sugars, [[polysaccharides]] and [[ectoenzyme]]s, and collectively account for 40% of root carbon.<ref>{{cite book |title=Mineral Nutrition of Higher Plants |last1= Marschner|first1=Horst |year= 1995  |isbn=0124735436 }}</ref> Exudation of these compounds has various benefits to the plant and to the [[microorganisms]] of the rhizosphere.<ref>{{Cite journal | last1 = Walker | first1 = T. S. | last2 = Bais | first2 = H. P. | last3 = Grotewold | first3 = E. | last4 = Vivanco | first4 = J. M. | title = Root Exudation and Rhizosphere Biology | doi = 10.1104/pp.102.019661 | journal = Plant Physiology | volume = 132 | issue = 1 | pages = 44–51 | year = 2003 | pmid =  12746510| pmc =1540314 }}</ref><ref>{{Cite journal | last1 = Martins | first1 = S. J. | last2 = Medeiros | first2 = F. H. V. | last3 = Lakshmanan | first3 = V. | last4 = Bais | first4 = H. P. | title = Impact of Seed Exudates on Growth and Biofilm Formation of Bacillus amyloliquefaciens ALB629 in Common Bean | doi = 10.3389/fmicb.2017.02631 | pmid = 29375501 | pmc = 5767182 | journal = Frontiers in Microbiology | volume = 8 | pages = 2631 | year = 2018 | doi-access = free }}</ref>

==See also==
* [[Honeydew (secretion)]]
* [[Guttation]]
* [[Pleural effusion#Exudative|Pleural effusion]]
* [[Scarless wound healing]]
* [[Surfactant leaching]]

==References==
{{reflist|30em}}

==External links==
* {{Commons category-inline}}

{{Disorders of volume state}}
{{Inflammation}}
{{Authority control}}

[[Category:Cardiovascular physiology]]
[[Category:Body fluids]]