Editing Triple test (section)

{{Short description|Investigation performed during pregnancy in the 2nd trimester to check chromosomal abnormalities}}
{{distinguish|text=[[Triple test score]], a diagnostic tool for examining potentially cancerous breasts}}
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{{Infobox diagnostic
| name            = Triple test
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| test of         =chromosomal abnormalities
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| synonyms        = Triple  screen,Bart's test
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The '''triple test''', also called  '''triple screen''', the '''Kettering test''' or the '''Bart's test''', is an investigation performed during [[pregnancy]] in the second trimester to classify a patient as either high-risk or low-risk for chromosomal abnormalities (and neural tube defects).

The term "multiple-marker screening test" is sometimes used instead.<ref name="pmid9572446">{{cite journal |vauthors=Renier MA, Vereecken A, Van Herck E, Straetmans D, Ramaekers P, Buytaert P |title=Second trimester maternal dimeric inhibin-A in the multiple-marker screening test for Down's syndrome |journal=Hum. Reprod. |volume=13 |issue=3 |pages=744–8 |date=March 1998 |pmid=9572446 |doi= 10.1093/humrep/13.3.744|url=http://humrep.oxfordjournals.org/cgi/pmidlookup?view=long&pmid=9572446|doi-access=free }}</ref><ref name="pmid14586337">{{cite journal |vauthors=Yudin MH, Prosen TL, Landers DV |title=Multiple-marker screening in human immunodeficiency virus-positive pregnant women: Screen positivity rates with the triple and quad screens |journal=Am. J. Obstet. Gynecol. |volume=189 |issue=4 |pages=973–6 |date=October 2003 |pmid=14586337 |doi= 10.1067/S0002-9378(03)01053-6}}</ref> This term can encompass the "double test" and "quadruple test" (described below).

The Triple screen measures [[Blood serum|serum]] levels of [[Alpha-fetoprotein|AFP]], [[estriol]], and [[beta-hCG]], with a 70% [[sensitivity and specificity|sensitivity]] and 5% [[false-positive]] rate.  It is complemented in some regions of the United States, as the ''Quad screen'' (adding inhibin A to the panel, resulting in an 81% sensitivity and 5% false-positive rate for detecting [[Down syndrome]] when taken at 15–18 weeks of [[Gestational age (obstetrics)|gestational age]])<ref>{{cite journal|doi = 10.1258/jms.2009.009017|title= The ability of the quadruple test to predict adverse perinatal outcomes in a high-risk obstetric population|pmid=    19564516|last1 = Lao|first1 =  M.R.|last2 = Calhoun|first2= B. C.|last3 =  Bracero|first3= L. A.|last4 = Wang|first4= Y.|last5= Seybold|first5= D. J.|last6= Broce |first6=M.|last7= Hatjis |first7=C. G.|journal=J Med Screen|year=2009|volume=16|issue=2|pages=55–59 |s2cid= 23214929}}</ref> and other [[prenatal diagnosis]] techniques, although it remains widely used in Canada<ref>[http://www.sogc.org/health/pregnancy-prenatal_e.asp sogc.org] {{Webarchive|url=https://web.archive.org/web/20090628121155/http://www.sogc.org/health/pregnancy-prenatal_e.asp |date=2009-06-28 }}</ref> and other countries. A positive screen indicates an increased risk of chromosomal abnormalities (and neural tube defects), and such patients are then referred for more sensitive and specific procedures to receive a definitive diagnosis, often prenatal diagnosis via [[amniocentesis]], although the stronger screening option of [[cell-free fetal DNA]] screening (also popularly known as noninvasive prenatal screening) is frequently offered. The Triple test can be understood as an early predecessor to a long line of subsequent technological improvements.  In some American states, such as Missouri, Medicaid reimburses only for the Triple test and not other potentially more accurate screening tests, whereas California offers Quad tests to all pregnant women.<ref>[http://www.cdph.ca.gov/programs/pns/Documents/Provider%20Handbook%20%202009%20WEB.pdf cdph.ca.gov] {{Webarchive|url=https://web.archive.org/web/20170212001459/http://www.cdph.ca.gov/programs/pns/Documents/Provider%20Handbook%20%202009%20WEB.pdf |date=2017-02-12 }}</ref>

While the triple test can be performed at any point between 15 and 21.9 weeks of gestation, the highest detection rate for open neural defects is given by a test performed between 16 and 18 weeks of gestation.<ref>{{cite web |title=Understanding the Triple Test |url=https://www.sonoraquest.com/patient/knowledge-center/understanding-the-triple-test/ |website=Sonora Quest Laboratories |access-date=1 February 2023}}</ref>