View source for Rapid plasma reagin

{{short description|Test for syphilis}}

{{Infobox diagnostic
| name            = Rapid plasma reagin
| image           = Image:TreponemaPallidum.jpg|
| alt             =
| caption         = ''[[Treponema pallidum]]'', the bacterium that causes [[syphilis]]
| pronounce       =
| purpose         =test to indicate a syphilis infection
| test of         =
| based on        =
| synonyms        = RPR titer
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The '''rapid plasma reagin test''' ('''RPR test''' or '''RPR titer''') is a type of [[rapid diagnostic test]] that looks for non-specific [[antibody|antibodies]] in the blood of the patient that may indicate an infection by [[syphilis]] or related non-venereal [[treponematoses]]. It is one of several [[nontreponemal tests for syphilis]] (along with the [[Wassermann test]] and the [[VDRL test]]). The term ''reagin'' means that this test does not look for antibodies against the bacterium itself, ''[[Treponema pallidum]]'', but rather for antibodies against substances released by cells when they are damaged by ''T. pallidum'' ([[cardiolipin]] and [[lecithin]]). Traditionally, syphilis serologic testing has been performed using a nontreponemal test (NTT) such as the RPR or VDRL test, with positive results then confirmed using a specific [[treponemal test]] (TT) such as [[Treponema pallidum particle agglutination assay|TPPA]] or [[Fluorescent treponemal antibody absorption test|FTA-ABS]]. This method is endorsed by the U.S. [[Centers for Disease Control and Prevention]] (CDC) and is the standard in many parts of the world. After screening for syphilis, a [[titer]] can be used to track the progress of the disease over time and its response to therapy.<ref name="auto">{{Cite journal |doi = 10.1128/CVI.00681-14|pmid = 25428245|pmc = 4308867|title = Recent Trends in the Serologic Diagnosis of Syphilis|journal = Clinical and Vaccine Immunology|volume = 22|issue = 2|pages = 137–147|year = 2015|last1 = Morshed|first1 = Muhammad G.|last2 = Singh|first2 = Ameeta E.}}</ref>
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==Accuracy==
The RPR test is an effective [[screening test]] that is very good at detecting syphilis in people without symptoms.<ref name=RedBookSyphilis>{{cite book |editor-first=Larry K. |editor-last=Pickering |title=Red Book: 2006 Report of the Committee on Infectious Diseases |chapter=Syphilis |isbn=1581101945 |publisher=American Academy of Pediatrics |year=2006 |pages=[https://archive.org/details/redbook2006repor00elkg/page/631 631–644] |oclc=70819143 |chapter-url=https://archive.org/details/redbook2006repor00elkg/page/631 }}</ref> The NTT screening tests should always be followed up by a more specific [[treponemal test]]. Tests based on [[monoclonal antibodies]] and [[immunofluorescence]], including ''T. pallidum'' hemagglutination assay ([[TPHA]]) and fluorescent treponemal antibody absorption ([[FTA-ABS]]) are more specific and more expensive. Nontreponemal tests (NTT) measure levels of [[immunoglobulin G]] (IgG) and [[immunoglobulin M]] (IgM) antibodies produced by the host in response to lipoidal material (mostly cardiolipin) released from damaged host cells. It is also generally believed that some cardiolipin is released by the spirochetes.<ref name="auto"/>

==Alternatives==
Another test often used to screen for syphilis is the [[Venereal Disease Research Laboratory]] (VDRL) slide test. However, the RPR test is generally preferred due to its ease of use. Other types of tests are being evaluated as possible alternatives to standard manual RPR testing.  One of these alternatives is a fully automated RPR syphilis analyzer.<ref>{{cite web |url=http://www.arlingtonscientific.com/asi-evolution%c2%ae.html |title=Arlington Scientific {{!}} ASI Evolution®{{!}} ASI |website=www.arlingtonscientific.com |url-status=dead |archive-url=https://web.archive.org/web/20191118135231/http://www.arlingtonscientific.com/asi-evolution%C2%AE.html |archive-date=2019-11-18}} </ref> It also returns positive for other, non-venereal treponematoses. It has been recommended that a careful explanation of this fact be included with test results.<ref name=yaws>{{cite journal |last1=Marks |first1=M |last2=Lebari |first2=D |last3=Solomon |first3=AW |last4=Higgins |first4=SP |title=Yaws. |journal=International Journal of STD & AIDS |date=September 2015 |volume=26 |issue=10 |pages=696–703 |doi=10.1177/0956462414549036 |pmid=25193248 |pmc=4655361 |doi-access=free }}</ref>

==References==
{{reflist}}
* {{cite book |vauthors=Jameson JN, Kasper DL, Harrison TR, Braunwald E, Fauci AS, Hauser SL, Longo DL |title=Harrison's Principles of Internal Medicine |publisher=McGraw-Hill Medical Publishing Division |location=New York |year=2005 |edition=16th |isbn=0-07-140235-7 |url=http://highered.mcgraw-hill.com/sites/0071402357/information_center_view0/}}
* {{cite book |first1=Ronald A. |last1=Sacher |first2=Richard A. |last2=McPherson |first3=Joseph M. |last3=Campos |first4=Frances K. |last4=Widmann |title=Widmann's Clinical Interpretation of Laboratory Tests |year=2000 |publisher=Davis |isbn=978-0-8036-0270-0 |edition=2nd |oclc=42890290}}

{{Infectious and inflammatory blood tests}}
{{Clinical microbiology techniques}}

[[Category:Infectious disease blood tests]]