Sweat diagnostics

{{cs1 config|name-list-style=vanc}} {{Infobox diagnostic | name = Sweat diagnostics | image = | alt = | caption = | pronounce = | purpose =test for Eccrine sweat gland(mostly) | test of = | based on = | synonyms = | reference_range = | calculator = | DiseasesDB =  | ICD10 =  | ICD9 = | ICDO = | MedlinePlus =  | eMedicine =  | MeshID = | OPS301 =  | LOINC =  }} '''Sweat diagnostics''' is an emerging non-invasive technique used to provide insights to the health of the human body. Common sweat diagnostic tests include testing for cystic fibrosis<ref name="Mishra2005"/> and illicit drugs.<ref name="DeGiovanni2013"/> Most testing of human sweat is in reference to the eccrine sweat gland which in contrast to the apocrine sweat gland, has a lower composition of oils.<ref name="Wilke2007"/>

Although sweat is mostly water,<ref name="Wilke2007"/> there are many solutes which are found in sweat that have at least some relation to biomarkers found in blood. These include: sodium (Na+), chloride (Cl−), potassium (K+), ammonium (NH{{su|b=4|p=+}}), alcohols, lactate, peptides & proteins.<ref name="Sonner2015"/><ref name="Sato1989"/> Development of devices, sensing techniques and biomarker identification in sweat continues to be an expanding field for medical diagnostics and athletics applications.

The use of smart biosensors for on-skin sweat analysis has been described as internet-enabled Sudorology (iSudorology) by Brasier et al. in 2019. It describes the lab-independent detection of molecular, next-generation digital biomarkers in sweat.<ref>{{cite journal | vauthors = Brasier N, Eckstein J | title = Sweat as a Source of Next-Generation Digital Biomarkers | language = en | journal = Digital Biomarkers | volume = 3 | issue = 3 | pages = 155–165 | date = 2019 | pmid = 32095774 | pmc = 7011725 | doi = 10.1159/000504387 }}</ref>

==History== Some of the earliest, published studies<ref name="Hoelscher1899"/> on sweat composition date back to the 19th century. Further studies<ref name="Nyman1936"/><ref name="Schwartz1956"/><ref name="Sato1977"/> in the 20th century began to solidify understanding of the physiology and pharmacology of the eccrine sweat gland. In-vivo and in-vitro studies from this time period, and even those continuing today, have identified numerous structural nuances and new molecules present within sweat. The first commercially adopted use for sweat diagnostics included testing of sodium and chloride levels in children for the diagnosis of cystic fibrosis. Today, one of the most popular devices for this testing is the Macroduct Sweat Collection System from ELITechGroup.<ref name="Pullan2013"/>

==General evidence== More recently, numerous studies have identified the plausibility of sweat as an alternative to blood analysis.<ref name="Czarnowski1992"/><ref name="Cizza2008"/> The potential substitution for sweat versus blood analysis has many potential benefits. For example, sweat can be: extracted in a non-invasive manner via iontophoresis; extracted with little-to-no pain; and monitored continuously.<ref name="Banga1988"/> There are downfalls to the technology, however. For example, demonstration of successful and reliable sweat extraction and analysis on a cohesive device has yet to be demonstrated. Furthermore, although some biomarker partitioning mechanisms are well understood and well studied, partitioning of other useful biomarkers (cytokines, peptides, etc.) are less understood.<ref name="Sonner2015"/>

==Current research==

===Portable devices===

====Patches==== Patches have been demonstrated to be a promising detection platform for sweat diagnostics.<ref name="Scutti2014"/><ref name="Fenner2015"/><ref name="Begonia2014"/> Simple, long-term collection devices which check for drugs of abuse or alcohol are already on the market and operate on the following principle: a user applies the patch which then collects sweat over a period of hours or days, then the patch is analyzed utilizing techniques such as GC-MS which are accurate but have the drawback of lack of continuous measurements and high costs. For example, sweat diagnostic products for illicit drugs and alcohol are manufactured and supplied by PharmChek and AlcoPro, respectively. Recently several efforts<ref>{{cite journal | vauthors = Jain V, Ochoa M, Jiang H, Rahimi R, Ziaie B | title = A mass-customizable dermal patch with discrete colorimetric indicators for personalized sweat rate quantification | journal = Microsystems & Nanoengineering | volume = 5 | issue = 1 | pages = 29 | date = 2019-06-17 | pmid = 31240108 | pmc = 6572848 | doi = 10.1038/s41378-019-0067-0 | bibcode = 2019MicNa...5...29J }}</ref> have been made to develop low cost polymer based continuous perspiration monitoring devices and are in early stages of commercialization.<ref>{{Cite patent|title=Skin-mounted hydration sensor and management system|gdate=2017-10-02|country=US|number=10772560|pubdate=2020-09-15|assign=Purdue Research Foundation|inventor1-last=Ziaie|inventor1-first=Babak|inventor2-last=Ochoa|inventor2-first=Manuel P.|inventor3-last=Jain|inventor3-first=Vaibhav|inventor4-last=Rahimi|inventor4-first=Rahim}}</ref>

More recently, startup companies such as [http://www.Xsensio.com Xsensio] have begun developing products targeted towards the consumer, healthcare and athletics market for sweat diagnostics. Ultimately, it is the hope that these devices will have the ability to detect changes in human physiology within minutes without the need for repeated sample collection and analysis.<ref name="Heikenfeld2014"/>

====Temporary tattoos==== Temporary tattoo-based sweat diagnostic tools<ref name="Free2014"/> have been demonstrated by Dr. Joseph Wang's group from University of California, San Diego. Their work includes sweat diagnostics for sodium, lactate, ammonium, pH and biofuel opportunities.<ref name="Bandodkar2015"/>

== References == <references>

<ref name="Mishra2005">{{cite journal | vauthors = Mishra A, Greaves R, Massie J | title = The relevance of sweat testing for the diagnosis of cystic fibrosis in the genomic era | journal = The Clinical Biochemist. Reviews | volume = 26 | issue = 4 | pages = 135–53 | date = November 2005 | pmid = 16648884 | pmc = 1320177 }}</ref>

<ref name="DeGiovanni2013">{{cite journal | vauthors = De Giovanni N, Fucci N | title = The current status of sweat testing for drugs of abuse: a review | journal = Current Medicinal Chemistry | volume = 20 | issue = 4 | pages = 545–61 | date = 2013 | pmid = 23244520 | doi = 10.2174/0929867311320040006 }}</ref>

<ref name="Wilke2007">{{cite journal | vauthors = Wilke K, Martin A, Terstegen L, Biel SS | title = A short history of sweat gland biology | journal = International Journal of Cosmetic Science | volume = 29 | issue = 3 | pages = 169–79 | date = June 2007 | pmid = 18489347 | doi = 10.1111/j.1467-2494.2007.00387.x | doi-access = free }}</ref>

<ref name="Hoelscher1899">{{cite journal | vauthors = Hoelscher JH | title = A Study in Perspiration.: Original Research in One Hundred and Thirteen Cases.| journal = Journal of the American Medical Association | volume = 32 | pages = 1352–1360 | date = 1899 | doi = 10.1001/jama.1899.92450510001003 | url = https://zenodo.org/record/1447263 }}</ref>

<ref name="Nyman1936">{{cite journal | vauthors = Nyman E, Palmlöv A | title = The elimination of ethyl alcohol in sweat. | journal = Skandinavisches Archiv für Physiologie | volume = 74 | issue = 2 | pages = 155–159 | date = 1936 | doi = 10.1111/j.1748-1716.1936.tb01150.x }}</ref>

<ref name="Schwartz1956">{{cite journal | vauthors = Schwartz IL, Thaysen JH | title = Excretion of sodium and potassium in human sweat | journal = The Journal of Clinical Investigation | volume = 35 | issue = 1 | pages = 114–20 | date = January 1956 | pmid = 13278407 | pmc = 438784 | doi = 10.1172/JCI103245 }}</ref>

<ref name="Sato1977">{{cite journal | vauthors = Sato K | title = The physiology, pharmacology, and biochemistry of the eccrine sweat gland | journal = Reviews of Physiology, Biochemistry and Pharmacology | volume = 79 | pages = 51–131 | date = 1977 | pmid = 21440 | doi = 10.1007/BFb0037089 | isbn = 978-3-540-08326-9 }}</ref>

<ref name="Sonner2015">{{cite journal | vauthors = Sonner Z, Wilder E, Heikenfeld J, Kasting G, Beyette F, Swaile D, Sherman F, Joyce J, Hagen J, Kelley-Loughnane N, Naik R | title = The microfluidics of the eccrine sweat gland, including biomarker partitioning, transport, and biosensing implications | journal = Biomicrofluidics | volume = 9 | issue = 3 | pages = 031301 | date = May 2015 | pmid = 26045728 | pmc = 4433483 | doi = 10.1063/1.4921039 }}</ref>

<ref name="Heikenfeld2014">{{cite journal | vauthors = Heikenfeld J | url = https://spectrum.ieee.org/sweat-sensors-will-change-how-wearables-track-your-health | title = Sweat Sensors Will Change How Wearables Track Your Health | journal = IEEE Spectrum | date = 22 October 2014 }}</ref>

<ref name="Bandodkar2015">{{cite journal | vauthors = Bandodkar AJ, Jia W, Wang J | title = Tattoo-Based Wearable Electrochemical Devices: A Review | journal = Electroanalysis | volume = 27 | issue = 3 | pages = 562–572 | date = 2015 | doi = 10.1002/elan.201400537 }}</ref>

<ref name="Sato1989">{{cite journal | vauthors = Sato K, Kang WH, Saga K, Sato KT | title = Biology of sweat glands and their disorders. I. Normal sweat gland function | journal = Journal of the American Academy of Dermatology | volume = 20 | issue = 4 | pages = 537–63 | date = April 1989 | pmid = 2654204 | doi = 10.1016/s0190-9622(89)70063-3 }}</ref>

<ref name="Pullan2013">{{cite journal | vauthors = Pullan NJ, Thurston V, Barber S | title = Evaluation of an inductively coupled plasma mass spectrometry method for the analysis of sweat chloride and sodium for use in the diagnosis of cystic fibrosis | journal = Annals of Clinical Biochemistry | volume = 50 | issue = Pt 3 | pages = 267–70 | date = May 2013 | pmid = 23605131 | doi = 10.1177/0004563212474565 | s2cid = 40347024 }}</ref>

<ref name="Czarnowski1992">{{cite journal | vauthors = Czarnowski D, Górski J, Jóźwiuk J, Boroń-Kaczmarska A | title = Plasma ammonia is the principal source of ammonia in sweat | journal = European Journal of Applied Physiology and Occupational Physiology | volume = 65 | issue = 2 | pages = 135–7 | date = 1992 | pmid = 1396636 | doi = 10.1007/bf00705070 | s2cid = 7994016 }}</ref>

<ref name="Cizza2008">{{cite journal | vauthors = Cizza G, Marques AH, Eskandari F, Christie IC, Torvik S, Silverman MN, Phillips TM, Sternberg EM | title = Elevated neuroimmune biomarkers in sweat patches and plasma of premenopausal women with major depressive disorder in remission: the POWER study | journal = Biological Psychiatry | volume = 64 | issue = 10 | pages = 907–11 | date = November 2008 | pmid = 18657799 | pmc = 2610843 | doi = 10.1016/j.biopsych.2008.05.035 }}</ref>

<ref name="Banga1988">{{cite journal | vauthors = Banga AK, Chien YW | title = Iontophoretic delivery of drugs: fundamentals, developments and biomedical applications. | journal = Journal of Controlled Release | volume = 7 | pages = 1–24 | date = 1988 | doi = 10.1016/0168-3659(88)90075-2 }}</ref>

<ref name="Scutti2014">{{cite web | author-link = Susan Scutti | vauthors = Scutti S | url = https://www.medicaldaily.com/measuring-your-sweat-health-monitor-and-diagnostic-device-future-wearable-technology-308408 | title = Measuring Your Sweat, A Health Monitor And Diagnostic Device Is The Future Of Wearable Technology | work = Medical Daily | date = 29 October 2014 }}</ref>

<ref name="Free2014">{{cite web | first = Kathryn | last = Free | url = https://www.popularmechanics.com/science/health/a11097/temporary-tattoo-to-track-your-workout-2491688/ | title = A Temporary Tattoo to Track Your Workout and Charge Your Phone | work = Popular Mechanics | date = 13 August 2014 }}</ref>

<ref name="Fenner2015">{{cite web | first = Rudy | last = Fenner | url = http://www.businesswire.com/news/home/20150508005547/en/CoreSyte-Selected-Worldwide-Athletics-Partner-Eccrine-Systems#.VW27LPlVhBc | title = CoreSyte Selected as Worldwide Athletics Partner by Eccrine Systems | work = Business Wire | date = 8 May 2015 }}</ref>

<ref name="Begonia2014">{{cite web | first = Rose | last = Begonia | url = https://www.prnewswire.com/news-releases/kenzen-wearable-optimizes-athletic-performance-with-real-time-hydration-lactic-acid-and-glucose-analysis-300005504.html | title = Kenzen Wearable Optimizes Athletic Performance with Real-Time Hydration, Lactic Acid and Glucose Analysis | work = PR Newswire | date = 5 December 2014 }}</ref>

</references>

Category:Clinical chemistry Category:Skin tests