View source for Pap test

{{short description|Cervical screening test to detect potential cancers}}
{{redirect|Pap smear|the American musician|Pat Smear}}
{{more citations needed|date=July 2023}}
{{Infobox interventions
 | Name        = Papanicolaou test
 | Image       = High-grade squamous intraepithelial lesion.jpg
 | Caption     = High-grade squamous intraepithelial lesion
 | ICD10       =
 | ICD9        = {{ICD9|795.00}}
 | MeshID      = D014626
 | MedlinePlus = 003911
 | OtherCodes  =
}}
The '''Papanicolaou test''' (abbreviated as '''Pap test''', also known as '''Pap smear''' (AE),<ref>{{Cite web|url=https://medlineplus.gov/lab-tests/pap-smear/|title=Pap Smear: MedlinePlus Lab Test Information|website=medlineplus.gov|language=en|access-date=2018-11-07}}</ref> '''cervical smear''' (BE), '''cervical screening''' (BE),<ref>{{cite web |url=https://www.nhs.uk/conditions/cervical-screening/ |access-date=2018-09-04 |publisher=NHS |title=Cervical Screening|date=2017-10-20 }}</ref> or '''smear test''' (BE)) is a method of [[cervical screening]] used to detect potentially [[Precancerous condition|precancerous]] and [[cancer]]ous processes in the [[cervix]] (opening of the [[uterus]] or womb) or, more rarely, [[Human anus|anus]] (in both men and women).<ref>{{cite journal |last1=Lindsey |first1=Kimberley |last2=DeCristofaro |first2=Claire |last3=James |first3=Janet |title=Anal Pap smears: Should we be doing them? |journal=Journal of the American Academy of Nurse Practitioners |date=August 2009 |volume=21 |issue=8 |pages=437–443 |doi=10.1111/j.1745-7599.2009.00433.x|pmid=19689440 }}</ref> Abnormal findings are often followed up by more sensitive diagnostic procedures and, if warranted, interventions that aim to prevent progression to [[cervical cancer]]. The test was independently invented in the 1920s by the [[Greeks|Greek]] physician [[Georgios Papanikolaou]] and named after him. A simplified version of the test was introduced by the [[Canadians|Canadian]] obstetrician [[Anna Marion Hilliard]] in 1957.

A Pap smear is performed by opening the [[vagina]] with a [[speculum (medical)|speculum]] and collecting [[cell (biology)|cells]] at the outer opening of the cervix at the [[transformation zone]] (where the outer squamous cervical cells meet the inner glandular endocervical cells), using an [[Ayre spatula]] or a [[cytobrush]]. The collected cells are examined under a [[microscope]] to look for abnormalities. The test aims to detect potentially precancerous changes (called [[cervical intraepithelial neoplasia]] (CIN) or cervical dysplasia; the [[squamous intraepithelial lesion]] system (SIL) is also used to describe abnormalities) caused by [[human papillomavirus]], a sexually transmitted [[DNA virus]]. The test remains an effective, widely used method for early detection of precancer and cervical cancer. While the test may also detect infections and abnormalities in the [[Canal of the cervix|endocervix]] and [[endometrium]], it is not designed to do so.

Guidelines on when to begin Pap smear screening are varied, but usually begin in [[adult]]hood. Guidelines on frequency vary from every three to five years.<ref name="US2012">{{cite journal |last1=Moyer |first1=VA |last2=U.S. Preventive Services Task |first2=Force |date=Jun 19, 2012 |title=Screening for cervical cancer: U.S. Preventive Services Task Force recommendation statement. |journal=Annals of Internal Medicine |volume=156 |issue=12 |pages=880–91, W312 |doi=10.7326/0003-4819-156-12-201206190-00424 |pmid=22711081 |s2cid=36965456}}</ref><ref name=Saslow2012/><ref name="ACS">American Cancer Society. (2010). [http://www.cancer.org/Cancer/CervicalCancer/DetailedGuide/cervical-cancer-prevention Detailed Guide: Cervical Cancer. Can cervical cancer be prevented?] Retrieved August 8, 2011.</ref> If results are abnormal, and depending on the nature of the abnormality, the test may need to be repeated in six to twelve months.<ref name="ACOG">{{cite web | author = The American College of Obstetricians and Gynecologists | year = 2009 | url = http://www.acog.org/publications/patient_education/bp085.cfm | title = ACOG Education Pamphlet AP085&nbsp;– The Pap Test | location = Washington, DC. | access-date = June 5, 2010 | url-status = dead | archive-url = https://web.archive.org/web/20100615081510/http://www.acog.org/publications/patient_education/bp085.cfm | archive-date = June 15, 2010 }}</ref> If the abnormality requires closer scrutiny, the patient may be referred for detailed inspection of the cervix by [[colposcopy]], which magnifies the view of the cervix, vagina and vulva surfaces. The person may also be referred for [[HPV test|HPV DNA testing]], which can serve as an adjunct to Pap testing. In some countries, viral DNA is checked for first, before checking for abnormal cells.<ref>{{Cite web |date=2016-07-05 |title=Cervical cancer screening in England to use 'more accurate' viral DNA test |url=https://news.cancerresearchuk.org/2016/07/06/cervical-cancer-screening-in-england-to-use-more-accurate-viral-dna-test/ |access-date=2023-08-10 |website=Cancer Research UK - Cancer News |language=en-GB}}</ref> Additional biomarkers that may be applied as ancillary tests with the Pap test are evolving.<ref>{{Cite journal|last1=Shidham|first1=VinodB|last2=Mehrotra|first2=Ravi|last3=Varsegi|first3=George|last4=D′Amore|first4=Krista L|last5=Hunt|first5=Bryan|last6=Narayan|first6=Raj|date=2011-01-01|title=p16 INK4a immunocytochemistry on cell blocks as an adjunct to cervical cytology: Potential reflex testing on specially prepared cell blocks from residual liquid-based cytology specimens|journal=CytoJournal|language=en|volume=8|issue=1|pages=1|doi=10.4103/1742-6413.76379|pmc=045765|pmid=21369522 |doi-access=free }}</ref>

==Medical uses==
{| class="wikitable" style="float:right; width:40em; border:solid 1px #999; margin:0 0 1em 1em;"
|-
! colspan="3" style="background:#cee;"| Summary of reasons for testing
|-
! patient's characteristic
! indication
! rationale
|-
| under age 21, regardless of sexual history
| no test
| more harms than benefits<ref name="AAFPfive">{{Cite journal |author1 = American Academy of Family Physicians |author1-link = American Academy of Family Physicians |title = Five Things Physicians and Patients Should Question |journal = Choosing Wisely: An Initiative of the ABIM Foundation |url = http://www.aafp.org/dam/AAFP/documents/about_us/initiatives/choosing-wisely-five-questions.pdf |access-date = August 14, 2012  |archive-url = https://web.archive.org/web/20171111204956/http://www.aafp.org/dam/AAFP/documents/about_us/initiatives/choosing-wisely-five-questions.pdf |archive-date = November 11, 2017 |url-status = dead }}</ref>
|-
| age 20–25 until age 50–60
| test every 3–5 years if results normal
| broad recommendation<ref name=Arbyn10 />
|-
| over age 65; history of normal tests
| no further testing
| recommendation of [[United States Preventive Services Task Force|USPSTF]], [[American Congress of Obstetricians and Gynecologists|ACOG]], [[American Cancer Society|ACS]] and [[American Society for Clinical Pathology|ASCP]];<ref name=Saslow2012 /><ref name="stopscreening"/><ref name="agebenefit"/>
|-
| had total [[hysterectomy]] for non-cancer disease&nbsp;– [[cervix]] removed
| no further testing
| harms of screening after hysterectomy outweigh the benefits<ref name="AAFPfive"/>
|-
| had partial hysterectomy&nbsp;– cervix remains
| continue testing as normal
|
|-
| has received [[HPV vaccine]]
| continue testing as normal
| vaccine does not cover all cancer-causing types of HPV<ref name=Arbyn10 />
|-
| history of [[endometrial cancer]], with history of hysterectomy
| discontinue routine testing<ref name="SGOfive">{{Cite journal|author1 = Society of Gynecologic Oncology |author1-link = Society of Gynecologic Oncology |date = February 2014 |title = Five Things Physicians and Patients Should Question |journal = Choosing Wisely: An Initiative of the ABIM Foundation |url = http://www.choosingwisely.org/doctor-patient-lists/society-of-gynecologic-oncology/ |access-date = 19 February 2013}}, which cites
* {{cite journal |vauthors=Salani R, Backes FJ, Fung MF, Holschneider CH, Parker LP, Bristow RE, Goff BA | title = Posttreatment surveillance and diagnosis of recurrence in women with gynecologic malignancies: Society of Gynecologic Oncologists recommendations | journal = American Journal of Obstetrics and Gynecology | volume = 204 | issue = 6 | pages = 466–78 | year = 2011 | pmid = 21752752 | doi = 10.1016/j.ajog.2011.03.008 | doi-access = free }}
* {{cite journal |vauthors=Salani R, Nagel CI, Drennen E, Bristow RE | title = Recurrence patterns and surveillance for patients with early stage endometrial cancer | journal = Gynecologic Oncology | volume = 123 | issue = 2 | pages = 205–7 | year = 2011 | pmid = 21820709 | doi = 10.1016/j.ygyno.2011.07.014 }}
* {{cite journal |vauthors=Bristow RE, Purinton SC, Santillan A, Diaz-Montes TP, Gardner GJ, Giuntoli RL | title = Cost-effectiveness of routine vaginal cytology for endometrial cancer surveillance | journal = Gynecologic Oncology | volume = 103 | issue = 2 | pages = 709–13 | year = 2006 | pmid = 16797686 | doi = 10.1016/j.ygyno.2006.05.013 }}</ref>
| test no longer effective and likely to give false positive<ref name="SGOfive"/>
|-
|}
Screening guidelines vary from country to country. In general, screening starts about the age of 20 or 25 and continues until about the age of 50 or 60.<ref name="stopscreening">{{cite journal |last= Strander |first=B | title = At what age should cervical screening stop? | journal = Br Med J | volume = 338 | pages = 1022–23 | year = 2009 | pmid = 19395422 | doi = 10.1136/bmj.b809 | s2cid = 37206485 }}</ref> Screening is typically recommended every three to five years, as long as results are normal.<ref name=Arbyn10 />

[[American Congress of Obstetricians and Gynecologists]] (ACOG) and others recommend starting screening at age 21.<ref name=Saslow2012>{{cite journal |last1=Saslow |first1=Debbie |last2=Solomon |first2=Diane |last3=Lawson |first3=Herschel W. |last4=Killackey |first4=Maureen |last5=Kulasingam |first5=Shalini L. |last6=Cain |first6=Joanna M. |last7=Garcia |first7=Francisco A. R. |last8=Moriarty |first8=Ann T. |last9=Waxman |first9=Alan G. |last10=Wilbur |first10=David C. |last11=Wentzensen |first11=Nicolas |last12=Downs |first12=Levi S. |last13=Spitzer |first13=Mark |last14=Moscicki |first14=Anna-Barbara |last15=Franco |first15=Eduardo L. |last16=Stoler |first16=Mark H. |last17=Schiffman |first17=Mark |last18=Castle |first18=Philip E. |last19=Myers |first19=Evan R. |title=American Cancer Society, American Society for Colposcopy and Cervical Pathology, and American Society for Clinical Pathology Screening Guidelines for the Prevention and Early Detection of Cervical Cancer |journal=Journal of Lower Genital Tract Disease |date=July 2012 |volume=16 |issue=3 |pages=175–204 |doi=10.1097/LGT.0b013e31824ca9d5 |pmid=22418039 |pmc=3915715}}</ref><ref name=ACOG2009>{{cite journal | title = ACOG Committee on Gynecologic Practice; Routine Pelvic Examination and Cervical Cytology Screening, Opinion #413 | journal = Obstetrics and Gynecology | volume = 113 | issue = 5 | pages = 1190–1193 | year = 2009 | pmid = 19384150 | doi = 10.1097/AOG.0b013e3181a6d022 | author1 = ACOG Committee on Gynecological Practice | doi-access = free }}</ref> Many other countries wait until age 25 or later to start screening. For instance, some parts of Great Britain start screening at age 25. ACOG's general recommendation is that people with female reproductive organs age 30–65 have an annual [[well-woman examination]], that they not get annual Pap tests, and that they do get Pap tests at three to five year intervals.<ref name="ACOGfive">{{Cite journal|author1 =  American Congress of Obstetricians and Gynecologists |author1-link = American Congress of Obstetricians and Gynecologists |title = Five Things Physicians and Patients Should Question |journal = Choosing Wisely: An Initiative of the ABIM Foundation |url = http://www.choosingwisely.org/doctor-patient-lists/american-college-of-obstetricians-and-gynecologists/ |access-date = August 1, 2013}}, which cites
* {{cite journal |vauthors=Boulware LE, Marinopoulos S, Phillips KA, Hwang CW, Maynor K, Merenstein D, Wilson RF, Barnes GJ, Bass EB, Powe NR, Daumit GL | title = Systematic review: The value of the periodic health evaluation | journal = Annals of Internal Medicine | volume = 146 | issue = 4 | pages = 289–300 | year = 2007 | pmid = 17310053 | doi=10.7326/0003-4819-146-4-200702200-00008| s2cid = 1683342 | doi-access = free }}
* {{cite journal |vauthors=Saslow D, Solomon D, Lawson HW, Killackey M, Kulasingam SL, Cain J, Garcia FA, Moriarty AT, Waxman AG, Wilbur DC, Wentzensen N, Downs LS, Spitzer M, Moscicki AB, Franco EL, Stoler MH, Schiffman M, Castle PE, Myers ER | title = American Cancer Society, American Society for Colposcopy and Cervical Pathology, and American Society for Clinical Pathology screening guidelines for the prevention and early detection of cervical cancer | journal = CA Cancer J Clin | volume = 62 | issue = 3 | pages = 147–72 | year = 2012 | pmid = 22422631 | pmc = 3801360 | doi = 10.3322/caac.21139 }}
* {{cite journal | title = Committee Opinion No. 534 | journal = Obstetrics & Gynecology | volume = 120 | issue = 2, Part 1 | pages = 421–424 | year = 2012 | pmid = 22825111 | doi = 10.1097/AOG.0b013e3182680517 | author1 = Committee on Gynecologic Practice }}
* {{cite journal | title = ACOG Practice Bulletin Number 131: Screening for cervical cancer | journal = Obstetrics and Gynecology | volume = 120 | issue = 5 | pages = 1222–1238 | year = 2012 | pmid = 23090560 | doi = 10.1097/AOG.0b013e318277c92a | author1 = Committee on Practice Bulletins—Gynecology }}</ref>

HPV is passed through skin to skin contact; sex does not have to occur, although it is a common way for it to spread.<ref>{{Cite web|url=https://www.cancer.org/cancer/cervical-cancer/prevention-and-early-detection/can-cervical-cancer-be-prevented.html|title=Can Cervical Cancer Be Prevented?|website=www.cancer.org|language=en|access-date=2018-11-07}}</ref> It takes an average of a year, but can take up to four years, for a person's immune system to clear the initial infection. Screening during this period may show this immune reaction and repair as mild abnormalities, which are usually not associated with cervical cancer, but could cause the patient stress and result in further tests and possible treatment. Cervical cancer usually takes time to develop, so delaying the start of screening a few years poses little risk of missing a potentially precancerous lesion. For instance, screening people under age 25 does not decrease cancer rates under age 30.<ref>{{cite journal|author1=Sasieni, P |author2=Castanon, A |author3=Cuzick, J |author4=Snow, J | title = Effectiveness of Cervical Screening with Age: Population based Case-Control Study of Prospectively Recorded Data | journal = BMJ | volume = 339| pages = 2968–2974 | year = 2009 | doi=10.1136/bmj.b2968|pmid=19638651 |pmc=2718082 }}</ref>

HPV can be transmitted in sex between females, so those who have only had sex with other females should be screened, although they are at somewhat lower risk for cervical cancer.<ref name=Marrazzo2001>{{cite journal |vauthors=Marrazzo JM, Koutsky LA, Kiviat NB, Kuypers JM, Stine K | title = Papanicolaou test screening and prevalence of genital human papillomavirus among women who have sex with women | journal = American Journal of Public Health | volume = 91 | issue = 6 | pages = 947–952 | year = 2001 | pmid = 11392939 | pmc = 1446473 | doi = 10.2105/AJPH.91.6.947 }}</ref>

Guidelines on frequency of screening vary—typically every three to five years for those who have not had previous abnormal smears.<ref name=Arbyn10 /> Some older recommendations suggested screening as frequently as every one to two years, however there is little evidence to support such frequent screening; annual screening has little benefit but leads to greatly increased cost and many unnecessary procedures and treatments.<ref name=Saslow2012 /> It has been acknowledged since before 1980 that most people can be screened less often.<ref>{{cite journal| quote = ACS and others have recommended, since before 1980, that conventional cytology can be safely performed up to every three years for most women. | author = Smith, RA| title = American Cancer Society Guideline for the Early Detection of Cervical Neoplasia and Cancer | journal = CA: A Cancer Journal for Clinicians| volume = 52 | issue = 1 | pages = 8–22 | year = 2002 | doi = 10.3322/canjclin.52.6.342| pmid = 12469763| s2cid = 19919545|display-authors=etal| doi-access = free}}</ref> In some guidelines, frequency depends on age; for instance in Great Britain, screening is recommended every three years for women under 50, and every five years for those over.<ref>{{cite web |title=Cervical screening: programme overview |url=https://www.gov.uk/guidance/cervical-screening-programme-overview |website=Gov.UK |publisher=Public Health England |access-date=21 June 2023}}</ref>

Screening should stop at about age 65 unless there is a history of abnormal test result or disease. There is probably no benefit in screening people aged 60 or over whose previous tests have been negative.<ref name="agebenefit">{{cite journal |vauthors=Sasieni P, Adams J, Cuzick J | title = Benefit of cervical screening at different ages: evidence from the UK audit of screening histories | journal = Br J Cancer | volume = 89 | issue = 1 | pages = 88–93 | year = 2003 | pmid = 12838306 | pmc = 2394236 | doi = 10.1038/sj.bjc.6600974 }}</ref> If a woman's last three Pap results were normal, she can discontinue testing at age 65, according to the USPSTF, ACOG, ACS, and ASCP;<ref name=Saslow2012 /> England's NHS says 64. There is no need to continue screening after a complete hysterectomy for benign disease.

Pap smear screening is still recommended for those who have been [[HPV vaccine|vaccinated against HPV]]<ref name=Arbyn10 /> since the vaccines do not cover all HPV types that can cause cervical cancer. Also, the vaccine does not protect against HPV exposure before vaccination.<ref>{{cite web |title=HPV Vaccination Recommendations |url=https://www.cdc.gov/vaccines/vpd/hpv/hcp/recommendations.html |website=Centers for Disease Prevention and Control |date=22 May 2023 |access-date=21 June 2023}}</ref>

Those with a history of [[endometrial cancer]] should discontinue routine Pap tests after hysterectomy.<ref name="SGOfive"/><ref>{{Cite journal|last=Salani|first=R|date=2017|title=An update on post-treatment surveillance and diagnosis of recurrence in women with gynecologic malignancies: Society of Gynecologic Oncology (SGO) recommendations|url=https://www.sgo.org/wp-content/uploads/2017/06/Salani-paper.pdf |archive-url=https://web.archive.org/web/20190702163850/https://www.sgo.org/wp-content/uploads/2017/06/Salani-paper.pdf |archive-date=2019-07-02 |url-status=live|journal=Gynecologic Oncology|volume=146|issue=1|pages=3–10|doi=10.1016/j.ygyno.2017.03.022|pmid=28372871}}</ref> Further tests are unlikely to detect recurrence of cancer but do bring the risk of giving false positive results, which would lead to unnecessary further testing.<ref name="SGOfive"/>

More frequent Pap smears may be needed to follow up after an abnormal Pap smear, after treatment for abnormal Pap or biopsy results, or after treatment of cancer (cervical, anal, etc.).<ref>{{Cite web |date=2022-10-13 |title=HPV and Pap Test Results: Next Steps after an Abnormal Test - NCI |url=https://www.cancer.gov/types/cervical/screening/abnormal-hpv-pap-test-results |access-date=2024-02-25 |website=www.cancer.gov |language=en}}</ref>

===Effectiveness===
The Pap test, when combined with a regular program of screening and appropriate follow-up, can reduce cervical cancer deaths by up to 80%.<ref name=Arbyn10>{{cite journal |vauthors=Arbyn M, Anttila A, Jordan J, Ronco G, Schenck U, Segnan N, Wiener H, Herbert A, von Karsa L | title = European Guidelines for Quality Assurance in Cervical Cancer Screening. Second Edition—Summary Document | journal = Annals of Oncology | volume = 21 | issue = 3 | pages = 448–458 | year = 2010 | pmid = 20176693 | pmc = 2826099 | doi = 10.1093/annonc/mdp471 }}</ref>

Failure of prevention of cancer by the Pap test can occur for many reasons, including not getting regular screening, lack of appropriate follow-up of abnormal results, and sampling and interpretation errors.<ref name=DeMay>{{cite book| author = DeMay, M. | year = 2007 | title = Practical principles of cytopathology. Revised edition. | isbn = 978-0-89189-549-7| publisher = American Society for Clinical Pathology Press| location = Chicago, IL}}</ref> In the US, over half of all invasive cancers occur in females who have never had a Pap smear; an additional 10 to 20% of cancers occur in those who have not had a Pap smear in the preceding five years.{{citation needed|date=August 2024}} About one-quarter of US cervical cancers were in people who had an abnormal Pap smear but did not get appropriate follow-up (patient did not return for care, or clinician did not perform recommended tests or treatment).{{citation needed|date=May 2021}}

[[Adenocarcinoma]] of the cervix has not been shown to be prevented by Pap smears.<ref name=DeMay /> In the UK, which has a Pap smear screening program, adenocarcinoma accounts for about 15% of all cervical cancers.<ref>{{cite web | title=Cancer Research UK website | url=http://info.cancerresearchuk.org/cancerstats/types/cervix/incidence/ | access-date=2009-01-03 | url-status=dead | archive-url=https://web.archive.org/web/20090116222837/http://info.cancerresearchuk.org/cancerstats/types/cervix/incidence/ | archive-date=2009-01-16 }}</ref>

Estimates of the effectiveness of the United Kingdom's call and recall system vary widely, but it may prevent about 700 deaths per year in the UK.<ref name="pmid12714468">{{cite journal |vauthors=Raffle AE, Alden B, Quinn M, Babb PJ, Brett MT | title = Outcomes of screening to prevent cancer: analysis of cumulative incidence of cervical abnormality and modelling of cases and deaths prevented | journal = BMJ | volume = 326 | issue = 7395 | page = 901 | year = 2003 | pmid = 12714468 | pmc = 153831 | doi = 10.1136/bmj.326.7395.901 }}</ref>

Multiple studies have performed sensitivity and specificity analyses on Pap smears. Sensitivity analysis captures the ability of Pap smears to correctly identify women with cervical cancer. Various studies have revealed the sensitivity of Pap smears to be between 47.19 - 55.5%.<ref name=":0">{{Cite journal |date=December 2007 |title=Specificity, sensitivity and cost |url=https://www.nature.com/articles/nrc2287 |journal=Nature Reviews Cancer |language=en |volume=7 |issue=12 |pages=893 |doi=10.1038/nrc2287 |s2cid=43571578 |issn=1474-1768|url-access=subscription }}</ref><ref name=":1">{{Cite journal |last1=Najib |first1=Fatemeh sadat |last2=Hashemi |first2=Masooumeh |last3=Shiravani |first3=Zahra |last4=Poordast |first4=Tahereh |last5=Sharifi |first5=Sanam |last6=Askary |first6=Elham |date=September 2020 |title=Diagnostic Accuracy of Cervical Pap Smear and Colposcopy in Detecting Premalignant and Malignant Lesions of Cervix |journal=Indian Journal of Surgical Oncology |volume=11 |issue=3 |pages=453–458 |doi=10.1007/s13193-020-01118-2 |issn=0975-7651 |pmc=7501362 |pmid=33013127}}</ref><ref name=":2">{{Cite journal |last1=Nkwabong |first1=Elie |last2=Laure Bessi Badjan |first2=Ingrid |last3=Sando |first3=Zacharie |date=January 2019 |title=Pap smear accuracy for the diagnosis of cervical precancerous lesions |journal=Tropical Doctor |language=en |volume=49 |issue=1 |pages=34–39 |doi=10.1177/0049475518798532 |pmid=30222058 |s2cid=52280945 |issn=0049-4755|doi-access=free }}</ref> Specificity analysis captures the ability of Pap smears to correctly identify women without cervical cancer. Various studies have revealed the specificity of Pap smears to be between 64.79 - 96.8%.<ref name=":0" /><ref name=":1" /><ref name=":2" /> While Pap smears may not be entirely accurate, they remain one of the most effective cervical cancer prevention tools. Pap smears may be supplemented with HPV DNA testing.{{citation needed|date=October 2022}}

===Results===
In screening a general or low-risk population, most Pap results are normal.

In the United States, about 2–3 million abnormal Pap smear results are found each year.<ref name="emedicine">{{cite web |title=Pap Smear |url=http://www.emedicinehealth.com/pap_smear/article_em.htm |access-date=2008-12-27}}</ref> Most abnormal results are mildly abnormal ([[Bethesda system|ASC-US]] (typically 2–5% of Pap results) or low-grade squamous intraepithelial lesion ([[Bethesda System#LSIL|LSIL]]) (about 2% of results)), indicating HPV infection.{{citation needed|date=January 2009}} Although most low-grade cervical dysplasias spontaneously regress without ever leading to [[cervical cancer]], dysplasia can serve as an indication that increased vigilance is needed.

In a typical scenario, about 0.5% of Pap results are high-grade SIL ([[Bethesda System#HSIL|HSIL]]), and less than 0.5% of results indicate cancer; 0.2 to 0.8% of results indicate Atypical Glandular Cells of Undetermined Significance (AGC-NOS).{{citation needed|date=January 2009}}

As liquid-based preparations (LBPs) become a common medium for testing, atypical result rates have increased. The median rate for all preparations with low-grade squamous intraepithelial lesions using LBPs was 2.9% in 2006, compared with a 2003 median rate of 2.1%. Rates for high-grade squamous intraepithelial lesions (median, 0.5%) and atypical squamous cells have changed little.<ref>{{cite journal |vauthors=Eversole GM, Moriarty AT, Schwartz MR, Clayton AC, Souers R, Fatheree LA, Chmara BA, Tench WD, Henry MR, Wilbur DC |year=2010 |title=Practices of participants in the college of american pathologists interlaboratory comparison program in cervicovaginal cytology, 2006 |url=https://meridian.allenpress.com/aplm/article/134/3/331/460995/Practices-of-Participants-in-the-College-of |journal=Archives of Pathology & Laboratory Medicine |volume=134 |issue=3 |pages=331–5 |doi=10.5858/134.3.331 |pmid=20196659|url-access=subscription }}</ref>

Abnormal results are reported according to the [[Bethesda system]].<ref>{{Cite journal|last1=Nayar|first1=Ritu|last2=Solomon|first2=Diane|date=2004-01-01|title=Second edition of 'The Bethesda System for reporting cervical cytology' - Atlas, website, and Bethesda interobserver reproducibility project|journal=CytoJournal|language=en|volume=1|issue=1|page=4|doi=10.1186/1742-6413-1-4|pmc=526759|pmid=15504231 |doi-access=free }}</ref> They include:<ref name="emedicine" />

* Atypical squamous cells (ASC)
** Atypical squamous cells of undetermined significance (ASC-US)
** Atypical squamous cells&nbsp;– cannot exclude HSIL (ASC-H)
* Squamous intraepithelial lesion (SIL)
** Low-grade squamous intraepithelial lesion (LGSIL or LSIL)
** High-grade squamous intraepithelial lesion (HGSIL or HSIL)
* [[Squamous cell carcinoma]]
* Glandular epithelial cell abnormalities
** Atypical glandular cells not otherwise specified (AGC or AGC-NOS)

Endocervical and endometrial abnormalities can also be detected, as can a number of infectious processes, including [[Candida albicans|yeast]], [[herpes simplex virus]] and [[trichomoniasis]]. However it is not very sensitive at detecting these infections, so absence of detection on a Pap does not mean absence of the infection.<ref>{{Cite journal |last1=González Pedraza Avilés |first1=A. |last2=Ortiz Zaragoza |first2=C. |last3=Topete Barrera |first3=L. |last4=Mota Vázquez |first4=R. |last5=Ponce Rosas |first5=R. |date=2001-03-15 |title=[Is the Papanicolaou smear useful as aid for diagnosing some sexually transmitted infections?] |journal=Atencion Primaria |volume=27 |issue=4 |pages=222–226 |doi=10.1016/S0212-6567(01)78800-2 |issn=0212-6567 |pmc=7684047 |pmid=11262330}}</ref>

<gallery class="center">
Image:Normal PAP (Cervical) Smear.jpg|[[Micrograph]] of a normal pap smear
Image:Low-grade sil and endocx.jpg|[[Micrograph]] of a Pap test showing a low-grade intraepithelial lesion (LSIL) and benign [[endocervix|endocervical]] mucosa. [[Pap stain]].
Image:Trichomonas pap test.jpg|[[Micrograph]] of a Pap test showing [[trichomoniasis]]. Trichomonas organism seen in the upper right. [[Pap stain]].
Image:Herpes simplex virus pap test.jpg|[[Micrograph]] of a Pap test showing changes of [[herpes simplex virus]]. [[Pap stain]].
Image:Adenocarcinoma on pap test 1.jpg|Endocervical [[adenocarcinoma]] on a pap test.
Image:Candida pap 1.jpg|[[Candida (genus)|Candida]] organisms on a pap test.
Image:Herpes_simplex_virus_pap_test.jpg|Viral cytopathic effect consistent with [[herpes simplex virus]] on a pap test.
Image:Pap test normal.jpg|Normal squamous epithelial cells in [[premenopausal]] women
Image:Pap test atropy.JPG|Atrophic squamous cells in [[postmenopausal]] women
Image:Pap test endocervical cells.JPG|Normal [[Canal of the cervix|endocervical cells]] should be present into the slide, as a proof of a good quality sampling
Image:Pap test citolysis.JPG|The cytoplasms of squamous [[Epithelium|epithelial cells]] melted out; many [[Vaginal flora|Döderlein]] bacilli can be seen.
Image:Pap test trichomonas.JPG|Infestation by [[Trichomonas vaginalis]]
Image:Pap test abnormal.JPG|An obviously atypical cell can be seen
</gallery>

===Pregnancy===
Pap tests can usually be performed during pregnancy up to at least 24 weeks of [[Gestational age (obstetrics)|gestational age]].<ref name=victoria>[http://www.papscreen.org.au/forwomen/whoshouldhavepaptests/pregnantwomen PapScreen Victoria > Pregnant women] {{Webarchive|url=https://web.archive.org/web/20140201225635/http://www.papscreen.org.au/forwomen/whoshouldhavepaptests/pregnantwomen |date=2014-02-01 }} from Cancer Council Victoria 2014</ref> Pap tests during pregnancy have not been associated with increased risk of [[miscarriage]].<ref name="victoria" /> An inflammatory component is commonly seen on Pap smears from pregnant women<ref>[http://deepblue.lib.umich.edu/bitstream/handle/2027.42/35304/1_ftp.pdf?sequence=1] {{cite journal |author=Michael CW |year=1999 |title=The Papanicolaou Smear and the Obstetric Patient: A Simple Test with Great Benefits |journal=Diagnostic Cytopathology |volume=21 |issue=1 |pages=1–3 |doi=10.1002/(SICI)1097-0339(199907)21:1<1::AID-DC1>3.0.CO;2-0 |pmid=10405797 |s2cid=1367319 |hdl-access=free |hdl=2027.42/35304}}</ref> and does not appear to be a risk for subsequent [[preterm birth]].<ref>{{cite journal |vauthors=Lanouette JM, Puder KS, Berry SM, Bryant DR, Dombrowski MP | title = Is inflammation on Papanicolaou smear a risk factor for preterm delivery? | journal = Fetal Diagnosis and Therapy | volume = 12 | issue = 4 | pages = 244–247 | year = 1997 | pmid = 9354886 | doi=10.1159/000264477}}</ref>

After childbirth, it is recommended to wait 12 weeks before taking a Pap test because inflammation of the cervix caused by the birth interferes with test interpretation.<ref>{{cite web |url=http://www.papscreen.org.au/forwomen/whoshouldhavepaptests/pregnantwomen |title=Pregnant women |author=<!--Staff writer(s); no by-line.--> |website=papscreen.org |publisher=[[Cancer Council Victoria]] |access-date=2015-01-16 |archive-url=https://web.archive.org/web/20150108193521/http://www.papscreen.org.au/forwomen/whoshouldhavepaptests/pregnantwomen |archive-date=2015-01-08 |url-status=dead }}</ref>

=== In transgender individuals ===
Transgender men are also typically at risk for HPV due to retention of the uterine cervix in the majority of individuals in this subgroup.<ref>{{Cite book |last=Grant |first=Jaime M. |title=National Transgender Discrimination Survey report on health and health care : findings of a study by the National Center for Transgender Equality and the National Gay and Lesbian Task Force |date=2010 |publisher=National Center for Transgender Equality |oclc=707939280}}</ref><ref name=":4">{{Cite web |last= |date=2018-06-27 |title=Should trans men have cervical screening tests? |url=https://www.nhs.uk/common-health-questions/sexual-health/should-trans-men-have-cervical-screening-tests/ |access-date=2023-08-10 |website=[[NHS]] |language=en}}</ref> As such, professional guidelines recommend that transgender men be screened routinely for cervical cancer using methods such as Pap smear, identical to the recommendations for cisgender women.<ref>{{Cite journal |date=December 2011 |title=Committee Opinion No. 512: Health Care for Transgender Individuals |journal=Obstetrics & Gynecology |language=en |volume=118 |issue=6 |pages=1454–1458 |doi=10.1097/AOG.0b013e31823ed1c1 |pmid=22105293 |issn=0029-7844|doi-access=free }}</ref>

However, transgender men have lower rates of cervical cancer screening than cisgender women.<ref>{{Cite journal |last1=Peitzmeier |first1=Sarah M. |last2=Khullar |first2=Karishma |last3=Reisner |first3=Sari L. |last4=Potter |first4=Jennifer |date=December 2014 |title=Pap Test Use Is Lower Among Female-to-Male Patients Than Non-Transgender Women |url=https://linkinghub.elsevier.com/retrieve/pii/S0749379714003985 |journal=American Journal of Preventive Medicine |language=en |volume=47 |issue=6 |pages=808–812 |doi=10.1016/j.amepre.2014.07.031 |pmid=25455121|url-access=subscription }}</ref> Many transgender men report barriers to receiving gender-affirming healthcare,<ref>{{Cite book |last=Grant |first=Jaime M. |title=Injustice at every turn : a report of the National Transgender Discrimination Survey |date=2011 |publisher=National Center for Transgender Equality |oclc=777348181}}</ref><ref>{{Cite journal |last1=Snelgrove |first1=John W |last2=Jasudavisius |first2=Amanda M |last3=Rowe |first3=Bradley W |last4=Head |first4=Evan M |last5=Bauer |first5=Greta R |date=December 2012 |title="Completely out-at-sea" with "two-gender medicine": A qualitative analysis of physician-side barriers to providing healthcare for transgender patients |journal=BMC Health Services Research |language=en |volume=12 |issue=1 |pages=110 |doi=10.1186/1472-6963-12-110 |issn=1472-6963 |pmc=3464167 |pmid=22559234 |doi-access=free }}</ref> including lack of insurance coverage and stigma/discrimination<ref>{{Cite journal |last1=Poteat |first1=Tonia |last2=German |first2=Danielle |last3=Kerrigan |first3=Deanna |date=May 2013 |title=Managing uncertainty: A grounded theory of stigma in transgender health care encounters |url=https://linkinghub.elsevier.com/retrieve/pii/S0277953613001019 |journal=Social Science & Medicine |language=en |volume=84 |pages=22–29 |doi=10.1016/j.socscimed.2013.02.019|pmid=23517700 |s2cid=5339596 |url-access=subscription }}</ref><ref>{{Cite journal |last1=Reisner |first1=Sari L. |last2=Gamarel |first2=Kristi E. |last3=Dunham |first3=Emilia |last4=Hopwood |first4=Ruben |last5=Hwahng |first5=Sel |date=September 2013 |title=Female-to-Male Transmasculine Adult Health: A Mixed-Methods Community-Based Needs Assessment |url=http://journals.sagepub.com/doi/10.1177/1078390313500693 |journal=Journal of the American Psychiatric Nurses Association |language=en |volume=19 |issue=5 |pages=293–303 |doi=10.1177/1078390313500693 |pmid=23963876 |s2cid=3285779 |issn=1078-3903|url-access=subscription }}</ref> during clinical encounters, and may encounter provider misconceptions regarding risk in this population for cervical cancer. Pap smears may be presented to patients as non-gendered screening procedures for cancer rather than one specific for examination of the female reproductive organs. Pap smears may trigger gender dysphoria in patients and gender-neutral language can be used when explaining the pathogenesis of cancer due to infection, emphasizing the pervasiveness of HPV infection regardless of gender.<ref>{{Cite journal |last1=Potter |first1=Jennifer |last2=Peitzmeier |first2=Sarah M. |last3=Bernstein |first3=Ida |last4=Reisner |first4=Sari L. |last5=Alizaga |first5=Natalie M. |last6=Agénor |first6=Madina |last7=Pardee |first7=Dana J. |date=2015-07-10 |title=Cervical Cancer Screening for Patients on the Female-to-Male Spectrum: a Narrative Review and Guide for Clinicians |journal=Journal of General Internal Medicine |volume=30 |issue=12 |pages=1857–1864 |doi=10.1007/s11606-015-3462-8 |pmid=26160483 |pmc=4636588 |issn=0884-8734}}</ref>

Transgender women who have not had [[Vaginoplasty|vaginoplasties]] are not at risk of developing cervical cancer because they do not have cervices. Transgender women who have had vaginoplasties and have a neo-cervix or neo-vagina have a small chance of developing cancer, according to the Canadian Cancer Society.<ref>{{Cite web |title=As a trans woman, do I need to get screened for cervical cancer |url=https://cancer.ca/en/cancer-information/find-cancer-early/screening-in-lgbtq-communities/as-a-trans-woman-do-i-need-to-get-screened-for-cervical-cancer |publisher=Canadian Cancer Society}}</ref> Surgeons typically use penile skin to create the new vagina and cervix, which can contract HPV and lead to [[penile cancer]], although it is considerably rarer than cervical cancer.<ref name=":5">{{Cite web |date=2019-10-10 |title=I'm trans or non-binary, does this affect my cancer screening? |url=https://www.cancerresearchuk.org/about-cancer/cancer-symptoms/spot-cancer-early/screening/trans-and-non-binary-cancer-screening |access-date=2023-08-10 |website=Cancer Research UK |language=en}}</ref> Because the risk of this kind of cancer is so low, cervical cancer screening is not routinely offered for those with a neo-cervix.<ref>{{Cite web |date=2020-09-04 |title=Cervical screening for trans men and/or non-binary people |url=https://www.jostrust.org.uk/information/cervical-screening/trans-non-binary |access-date=2023-08-10 |website=Jo's Cervical Cancer Trust |language=en |author1=Anonymous }}</ref><ref name=":4" /><ref>{{Cite web |date=2023-03-17 |title=Tweet misleads on cervical cancer guidance for trans women |url=https://apnews.com/article/fact-check-cervical-cancer-trans-testing-249098855574 |access-date=2023-08-10 |website=AP News |language=en}}</ref><ref name=":5" />

==Procedure==
[[File:Taking pap-smear 1.png|thumb|Sample collection for thin-prep-cytology from the cervix uteri of a 39-years-old multiparous woman (4 pregnancies). The cervical brush is visible just before entering the cervix uteri.]]According to the CDC, intercourse, douching, and the use of vaginal medicines or spermicidal foam should be avoided for 2 days before the test.<ref name="CDCscreen">{{cite web |title=Screening for Cervical Cancer |url=https://www.cdc.gov/cervical-cancer/screening/index.html |website=[[CDC]] |access-date=15 August 2024 |date=26 October 2023}}</ref> A number of studies have shown that using a small amount of water-based gel lubricant does not interfere with, obscure, or distort the Pap smear. Further, cytology is not affected, nor are some STD testing.<ref>{{cite journal |author=Wright, Jessica L. |year=2010 |title=The Effect of Using Water-based Gel Lubricant During a Speculum Exam On Pap Smear Results |url=http://commons.pacificu.edu/pa/190/ |url-status=dead |journal=School of Physician Assistant Studies |archive-url=https://web.archive.org/web/20130524100341/http://commons.pacificu.edu/pa/190/ |archive-date=24 May 2013 |access-date=4 February 2012}}</ref> The CDC states that Pap smears can be performed during [[Menstrual cycle|menstruation]].<ref name="CDCscreen" /> However, the NHS recommends against cervical screening during, or in the 2 days before and after, menstruation.<ref>{{Cite web |date=2023-07-14 |title=How to book cervical screening |url=https://www.nhs.uk/conditions/cervical-screening/how-to-book/ |access-date=2023-08-13 |website=[[NHS]] |language=en}}</ref> Pap smears can be performed during menstruation, especially if the physician is using a liquid-based test; however if bleeding is extremely heavy, endometrial cells can obscure cervical cells, and if this occurs the test may need to be repeated in 6 months.<ref>{{Cite book |last=Chan |first=Paul D. |url=http://archive.org/details/gynecologyobstet0000chan |title=Gynecology and obstetrics : new treatment guidelines |date=2006 |publisher=Laguna Hills, CA : Current Clinical Strategies Pub. |others=Internet Archive |isbn=978-1-929622-63-4}}</ref>

Pap smears begin with the insertion of a [[speculum (medical)|speculum]] into the vagina, which spreads the vagina open and allows access to the [[cervix]]. The health care provider then collects a sample of cells from the outer opening or external '''os''' of the cervix by scraping it with either a spatula or brush.<ref>{{Cite web |date=2022-10-13 |title=Cervical Cancer Screening - NCI |url=https://www.cancer.gov/types/cervical/screening |access-date=2023-08-09 |website=www.cancer.gov |language=en}}</ref>

Obtaining a Pap smear should not cause much pain,<ref>{{cite web |title=Excerpts from Changing Bodies, Changing Lives |url=http://www.ourbodiesourselves.org/publications/cbclex5b.asp |url-status=dead |archive-url=https://web.archive.org/web/20131218085453/http://www.ourbodiesourselves.org/publications/cbclex5b.asp |archive-date=2013-12-18 |access-date=2013-07-02 |publisher=Our Bodies Ourselves}}</ref> but may be uncomfortable.<ref>{{Cite web |title=Cervical screening: support for people who feel anxious about attending |url=https://www.gov.uk/government/publications/cervical-screening-support-for-people-who-find-it-hard-to-attend/cervical-screening-support-for-people-who-feel-anxious-about-attending |access-date=2023-08-09 |website=GOV.UK |language=en}}</ref> Conditions such as [[vaginismus]], [[vulvodynia]], or [[stenosis of uterine cervix|cervical stenosis]] can cause insertion of the speculum to be painful.<ref>{{cite web |title=All About Speculums: Finding What Works for You |url=https://www.ohsu.edu/womens-health/all-about-speculums-finding-what-works-you |website=www.ohsu.edu |access-date=15 August 2024 |language=en}}</ref><ref>{{cite journal |last1=Biggs |first1=Kirsty V. |last2=Soo Hoo |first2=San |last3=Kodampur |first3=Mallikarjun |title=Mechanical dilatation of the stenosed cervix under local anesthesia: A prospective case series |journal=Journal of Obstetrics and Gynaecology Research |date=April 2022 |volume=48 |issue=4 |pages=956–965 |doi=10.1111/jog.15179 |pmid=35132727 |language=en |issn=1341-8076|pmc=9303640 }}</ref>

In a conventional Pap smear, the cells are placed on a glass slide and taken to the [[laboratory]] to be checked for abnormalities.<ref>{{Cite web |title=Conventional Pap Test |url=https://www.slh.wisc.edu/clinical/cytology/analytical-services/conventional-pap-smear/ |access-date=2023-08-09 |website=Wisconsin State Laboratory of Hygiene |language=en-US}}</ref>

A plastic-fronded broom is sometimes used in place of the spatula or brush. The broom is not as good a collection device, since it is much less effective at collecting endocervical material than the spatula and brush.<ref>{{cite journal |vauthors=Martin-Hirsch P, Lilford R, Jarvis G, Kitchener HC | title = Efficacy of cervical-smear collection devices: a systematic review and meta-analysis | journal = Lancet | volume = 354 | issue = 9192 | pages = 1763–1770 | year = 1999 | pmid = 10577637 | doi = 10.1016/S0140-6736(99)02353-3 | s2cid = 22733963 }}</ref> The broom is used more frequently with the advent of [[liquid-based cytology]], although either type of collection device may be used with either type of cytology.

The sample is stained using the [[Papanicolaou stain|Papanicolaou technique]], in which [[tinctorial]] dyes and acids are selectively retained by cells. Unstained cells cannot be seen adequately with a light microscope. Papanicolaou chose stains that highlighted cytoplasmic keratinization, which actually has almost nothing to do with the nuclear features used to make diagnoses now.{{Citation needed|date=August 2024}}

A single smear has an area of 25 x 50&nbsp;mm and contains a few hundred thousand cells on average. Screening with light microscopy is first done on low (10x) power and then switched to higher (40x) power upon viewing suspicious findings. Cells are analyzed under high power for morphologic changes indicative of malignancy (including enlarged and irregularly shaped nucleus, an increase in nucleus to cytoplasm ratio, and more coarse and irregular chromatin). Approximately 1,000 fields of view are required on 10x power for screening of a single sample, which takes on average 5 to 10 minutes.<ref>{{Cite journal |last1=Bengtsson |first1=Ewert |last2=Malm |first2=Patrik |date=2014 |title=Screening for Cervical Cancer Using Automated Analysis of PAP-Smears |journal=Computational and Mathematical Methods in Medicine |volume=2014 |pages=842037 |doi=10.1155/2014/842037 |issn=1748-670X |pmc=3977449 |pmid=24772188|doi-access=free }}</ref>

In some cases, a computer system may prescreen the slides, indicating those that do not need examination by a person or highlighting areas for special attention. The sample is then usually screened by a specially trained and qualified cytotechnologist using a light [[microscope]]. The terminology for who screens the sample varies according to the country; in the [[UK]], the personnel are known as [[cytoscreener]]s, [[biomedical scientist]]s (BMS), advanced practitioners and [[pathologist]]s. The latter two take responsibility for reporting the abnormal sample, which may require further investigation.{{Citation needed|date=August 2024}}

===Automated analysis===
Since the early 2000s, there have been successful attempts to develop automated, computer image analysis systems for screening.<ref name="pmid15842055">{{cite journal |vauthors=Biscotti CV, Dawson AE, Dziura B, Galup L, Darragh T, Rahemtulla A, Wills-Frank L |title=Assisted primary screening using the automated ThinPrep Imaging System |journal=Am. J. Clin. Pathol. |volume=123 |issue=2 |pages=281–7 |year=2005 |pmid=15842055 |doi=10.1309/AGB1MJ9H5N43MEGX |doi-access=free }}</ref> Although, on the available evidence, automated cervical screening could not be recommended for implementation into a national screening program, an NHS Health technology appraisal in 2005 concluded that the "general case for automated image analysis ha(d) probably been made".<ref>{{cite journal |vauthors=Willis BH, Barton P, Pearmain P, Bryan S, Hyde C |title=Cervical screening programmes: can automation help? Evidence from systematic reviews, an economic analysis and a simulation modelling exercise applied to the UK |journal=Health Technol. Assess. |year=2005 |volume=9 |issue=13 |pages=1-207, iii |doi=10.3310/hta9130 |pmid=15774236 |url=http://www.ncchta.org/fullmono/mon913.pdf }} {{Webarchive|url=https://web.archive.org/web/20080910144643/http://www.ncchta.org/fullmono/mon913.pdf|date=2008-09-10}}</ref> Automation may improve [[sensitivity (tests)|sensitivity]] and reduce unsatisfactory specimens.<ref name="pmid17604301">{{cite journal |vauthors=Davey E, d'Assuncao J, Irwig L, Macaskill P, Chan SF, Richards A, Farnsworth A | title = Accuracy of reading liquid based cytology slides using the ThinPrep Imager compared with conventional cytology: prospective study |journal=BMJ |volume=335 |issue=7609 |page=31 |year=2007 |pmid=17604301 |pmc=1910624 |doi=10.1136/bmj.39219.645475.55 }}</ref> Two systems have been approved by the FDA and function in high-volume reference laboratories, with human oversight.{{citation needed|reason=article|date=July 2007}}

===Types of screening===
{{for|other cervical screening tests and human papillomavirus testing|Cervical screening}}
* Conventional Pap—In a conventional Pap smear, samples are smeared directly onto a microscope slide after collection.
* Liquid-based cytology—The sample of (epithelial) cells is taken from the transitional zone, the squamocolumnar junction of the cervix, between the ectocervix and the endocervix. The cells taken are suspended in a bottle of preservative for transport to the laboratory, where they are analyzed using Pap stains.
[[File:Transformation zone types.png|thumb|240px|Transformation zone types, determining the Pap test location:<ref>International Federation for Cervical Pathology and Colposcopy (IFCPC) classification. References:<br>-{{cite web|url=https://www.rcpa.edu.au/Library/Practising-Pathology/Structured-Pathology-Reporting-of-Cancer/Docs/Transformation_zone|title=Transformation zone (TZ) and cervical excision types|website=[[:en:Royal College of Pathologists of Australasia|Royal College of Pathologists of Australasia]]}}<br>- {{cite journal|last1=Jordan|first1=J.|last2=Arbyn|first2=M.|last3=Martin-Hirsch|first3=P.|last4=Schenck|first4=U.|last5=Baldauf|first5=J-J.|last6=Da Silva|first6=D.|last7=Anttila|first7=A.|last8=Nieminen|first8=P.|last9=Prendiville|first9=W.|title=European guidelines for quality assurance in cervical cancer screening: recommendations for clinical management of abnormal cervical cytology, part 1|journal=Cytopathology|volume=19|issue=6|year=2008|pages=342–354|issn=0956-5507|doi=10.1111/j.1365-2303.2008.00623.x|pmid=19040546|s2cid=16462929|doi-access=free}}</ref><br>Type 1: Completely ectocervical.<br>Type 2: Endocervical component but fully visible.<br>Type 3: Endocervical component, not fully visible.]]
[[Image:Gray1167.svg|thumb|Cervix in relation to upper part of vagina and posterior portion of uterus.]]
[[File:Cytology of cervical squamous metaplasia.png|thumb|220px|Squamous metaplasia of the cervix, with typical features. Pap stain.]]

Pap tests commonly examine epithelial abnormalities, such as metaplasia, dysplasia, or borderline changes, all of which may be indicative of CIN. Nuclei will stain dark blue, squamous cells will stain green and keratinised cells will stain pink/ orange. Koilocytes may be observed where there is some dyskaryosis (of epithelium). The nucleus in koilocytes is typically irregular, indicating possible cause for concern; requiring further confirmatory screens and tests.

In addition, human papillomavirus (HPV) test may be performed either as indicated for abnormal Pap results, or in some cases, dual testing is done, where both a Pap smear and an HPV test are done at the same time (also called Pap co-testing).<ref>{{Cite journal |last1=Zhang |first1=Salina |last2=McNamara |first2=Megan |last3=Batur |first3=Pelin |date=June 2018 |title=Cervical Cancer Screening: What's New? Updates for the Busy Clinician |url=https://linkinghub.elsevier.com/retrieve/pii/S0002934318300950 |journal=The American Journal of Medicine |language=en |volume=131 |issue=6 |pages=702.e1–702.e5 |doi=10.1016/j.amjmed.2018.01.020|pmid=29408216 |s2cid=46780821 |url-access=subscription }}</ref>

===Practical aspects===
The endocervix may be partially sampled with the device used to obtain the ectocervical sample, but due to the anatomy of this area, consistent and reliable sampling cannot be guaranteed. Since abnormal endocervical cells may be sampled, those examining them are taught to recognize them.{{citation needed|date=November 2022}}

The endometrium is not directly sampled with the device used to sample the ectocervix. Cells may exfoliate onto the cervix and be collected from there, so as with endocervical cells, abnormal cells can be recognised if present but the Pap test should not be used as a screening tool for endometrial malignancy.{{citation needed|date=November 2022}}

In the United States, a Pap test itself costs $20 to $30, but the costs for Pap test visits can cost over $1,000, largely because additional tests are added that may or may not be necessary.<ref>{{cite journal | author = Bettigole C | title = The Thousand-Dollar Pap Smear | journal = New England Journal of Medicine | volume = 369 | issue = 16 | pages = 1486–1487 | year = 2013 | pmid = 24131176 | doi = 10.1056/NEJMp1307295 }}</ref>

==History==
The test was invented by and named after the Greek doctor [[Georgios Papanikolaou]], who started his research in 1923.<ref name=":3">{{Cite book |last1=Zheng |first1=Wenxin |chapter-url=https://books.google.com/books?id=hRegDwAAQBAJ&pg=PA572 |title=Gynecologic and Obstetric Pathology, Volume 2 |last2=Fadare |first2=Oluwole |last3=Quick |first3=Charles Matthew |last4=Shen |first4=Danhua |last5=Guo |first5=Donghui |date=2019-07-01 |publisher=Springer |isbn=978-981-13-3019-3 |language=en |chapter=History of Pap Test}}</ref> [[Aurel Babeș]] independently made similar discoveries in 1927.<ref>M.J. O'Dowd, E.E. Philipp, ''The History of Obstetrics & Gynaecology'', London, Parthenon Publishing Group, 1994, p. 547.</ref><ref>{{Cite journal |last=Pambuccian| first= Stefan E.| date =  2023 | title = Was the Cytologic Method for Cervical Cancer Diagnosis discovered by Serendipity or by Design (hypothesis-based Research)  | journal = Sudhoffs Archiv | volume = 107 | issue = 1 | pages = 55–83 | doi = 10.25162/sar-2023-0004 | issn=2366-2352}}</ref> However, Babeș' method was radically different from Papanikolaou's.<ref name=":3" /><ref>{{cite journal |vauthors=Diamantis A, Magiorkinis E, Androutsos G | date = Jul 2010 | title = What's in a name? Evidence that Papanicolaou, not Babeș, deserves credit for the Pap test | journal = Diagnostic Cytopathology | volume = 38 | issue = 7| pages = 473–6 | doi = 10.1002/dc.21226 | pmid = 19813255 | s2cid = 37757448 }}</ref>

The Pap test was finally recognized only after a leading article in the ''[[American Journal of Obstetrics and Gynecology]]'' in 1941 by Papanikolaou and Herbert F. Traut, an American gynecologist.<ref name=":3" /><ref>{{Cite journal |last1=Papanicolaou |first1=George N. |last2=Traut |first2=Herbert F. |date=1941 |title=The Diagnostic Value of Vaginal Smears in Carcinoma of the Uterus**This study has been aided by the Commonwealth Fund. Presented before the New York Obstetrical Society, March 11, 1941. |url=https://doi.org/10.1016/S0002-9378(16)40621-6 |journal=American Journal of Obstetrics and Gynecology |volume=42 |issue=2 |pages=193–206 |doi=10.1016/s0002-9378(16)40621-6 |issn=0002-9378}}</ref> A monograph titled ''Diagnosis of Uterine Cancer by the Vaginal Smear'' that they published contained drawings of the various cells seen in patients with no disease, inflammatory conditions, and preclinical and clinical carcinoma.<ref name=":3" /> The monograph was illustrated by [[Hashime Murayama]], who later became a staff illustrator with the [[National Geographic Society]].<ref name=":3" /> Both Papanikolaou and his wife, [[Andromachi Papanikolaou]], dedicated the rest of their lives to teaching the technique to other physicians and laboratory personnel.<ref name=":3" />

==Experimental techniques==

In the developed world, cervical biopsy guided by colposcopy is considered the "[[Gold standard (test)|gold standard]]" for diagnosing cervical abnormalities after an abnormal Pap smear. Other techniques such as [[triple smear]] are also done after an abnormal Pap smear.<ref>{{cite book|last1=Krunger|first1=TF|last2=Botha|first2=MH|title=Clinical gynaecology|date=2007|publisher=Juta|location=South Africa|page=23|edition=3|url=https://books.google.com/books?id=mEsPakNJWZYC&q=vce+smear&pg=PA21|access-date=7 December 2016|isbn=9780702173059}}</ref> The procedure requires a trained colposcopist and can be expensive to perform. However, Pap smears are very sensitive and some negative biopsy results may represent undersampling of the lesion in the biopsy, so negative biopsy with positive cytology requires careful follow-up.<ref>{{Cite journal|last1=Bewtra|first1=Chhanda|last2=Pathan|first2=Muhammad|last3=Hashish|first3=Hisham|date=2003-10-01|title=Abnormal Pap smears with negative follow-up biopsies: Improving cytohistologic correlations|journal=Diagnostic Cytopathology|language=en|volume=29|issue=4|pages=200–202|doi=10.1002/dc.10329|pmid=14506671|s2cid=40202036|issn=1097-0339}}</ref>

Experimental visualization techniques use broad-band light (e.g., direct visualization, [[speculoscopy]], [[cervicography]], visual inspection with acetic acid or with Lugol's, and colposcopy<!-- confusing? -->) and electronic detection methods (e.g., Polarprobe and ''in vivo'' [[spectroscopy]]). These techniques are less expensive and can be performed with significantly less training. They do not perform as well as Pap smear screening and colposcopy. At this point, these techniques have not been validated by large-scale trials and are not in general use.{{citation needed|date=November 2022}}

==Implementation by country==

=== Australia ===
Australia has used the Pap test as part of its cervical screening program since its implementation in 1991 which required women past the age of 18 be tested every two years.<ref>{{Cite web|title=Cervical cancer screening |url=https://www.cancer.org.au/cancer-information/causes-and-prevention/early-detection-and-screening/cervical-cancer-screening|access-date=2020-08-13|website=www.cancer.org.au|language=en}}</ref> In December 2017 Australia discontinued its use of the Pap test and replaced it with a new HPV test that is only required to be conducted once every five years from the age of 25.<ref>{{cite web |title=Cervical Screening|date=15 August 2019 |publisher=Australian Government Department of Health |url=http://www.cancerscreening.gov.au/internet/screening/publishing.nsf/Content/cervical-screening-1 |language=en|access-date=2020-08-13}}</ref> Medicare covers the costs of testing; however, if a patient's doctor does not allow bulk billing, they may have to pay for the appointment and then claim the Medicare rebate.<ref>{{Cite web|last=Cancer Institute of NSW|title=Do I need to pay for my cervical screen|url=https://www.cancer.nsw.gov.au/cervical-screening-nsw/your-cervical-screening-appointment/do-i-need-to-pay-for-my-cervical-screen|website=Cancer Institute NSW}}</ref>

=== Taiwan ===
Free Pap tests were offered from 1974–1984 before being replaced by a system in which all women over the age of 30 could have the cost of their Pap test reimbursed by the National Health Insurance in 1995.<ref>{{Cite journal |last1=Chen|first1=Y-Y|last2=You|first2=S-L|last3=Chen|first3=C-A|last4=Shih|first4=L-Y |last5=Koong|first5=S-L|last6=Chao|first6=K-Y|last7=Hsiao|first7=M-L|last8=Hsieh|first8=C-Y|last9=Chen |first9=C-J|date=2009-07-07 |title=Effectiveness of national cervical cancer screening programme in Taiwan: 12-year experiences|journal=British Journal of Cancer|volume=101|issue=1|pages=174–177 |doi=10.1038/sj.bjc.6605139|pmc=2713714|pmid=19536091 |issn=0007-0920}}</ref> This policy was still ongoing in 2018 and encouraged women to screen at least every three years.<ref>{{Cite journal|last1=Chen |first1=M.-J.|last2=Wu|first2=C.-Y.|last3=Chen|first3=R.|last4=Wang |first4=Y.-W.|date=2018-10-01 |title=HPV Vaccination and Cervical Cancer Screening in Taiwan|journal=Journal of Global Oncology |volume=4|issue=Supplement 2|pages=235s|doi=10.1200/jgo.18.94300|issn=2378-9506|doi-access=free}}</ref>

Despite this, the number of people receiving Pap tests remain lower than countries like Australia. Some believe this is due to a lack of awareness regarding the test and its availability. It has also been found that women who have chronic diseases or other reproductive diseases are less likely to receive the test.<ref>{{cite journal |author1=Fang-Hsin Leea |author2=Chung-Yi Lic |author3=Hsiu-Hung Wanga |author4=Yung-Mei Yang |title=The utilization of Pap tests among different female medical personnel: A nationwide study in Taiwan |journal=Preventive Medicine|volume=56 |issue=6 |pages=406–409 |year=2013 |doi=10.1016/j.ypmed.2013.03.001 |pmid=23524115}}</ref><ref>{{Cite web |url=https://www.iprojectmaster.com/NURSING/final-year-project-materials/knowledge-and-acceptability-of-cervical-cancer-screening-among-female-part-time-students|title=Knowledge of Cervical Cancer Screening among Women |website=iprojectmaster.com|language=en|access-date=2020-02-10}}</ref><ref>{{cite journal |vauthors=Peterson NB, Murff HJ, Cui Y, Hargreaves M, Fowke JH |title=Papanicolaou testing among women in the southern United States |journal=Journal of Women's Health |date=Jul–Aug 2008 |volume=17 |issue=6 |pages=939–946 |doi=10.1089/jwh.2007.0576 |pmc=2942751 |pmid=18582173}}</ref>

=== England ===
{{As of|2020}} the NHS maintains a cervical screening program in which women between the age of 25–49 are invited for a smear test every three years, and women past 50 every five years. Much like Australia, England uses a HPV test before examining cells that test positive using the Pap test.<ref>{{Cite web|title=Cervical screening (smear testing) {{!}} Health Information {{!}} Bupa UK|url=https://www.bupa.co.uk/health-information/womens-health/cervical-screening|access-date=2020-08-14|website=www.bupa.co.uk|language=en-GB}}</ref> The test is free as part of the national cervical screening program.<ref>{{Cite web|date=2013-08-30|title=About cervical screening|url=https://www.jostrust.org.uk/information/cervical-screening/what-is-cervical-screening|access-date=2020-08-14|website=Jo's Cervical Cancer Trust|language=en |author1=Admin }}</ref>

==Coccoid bacteria==
The finding of [[coccus|coccoid]] bacteria on a Pap test is of no consequence with otherwise normal test findings and no infectious symptoms. However, if there is enough inflammation to obscure the detection of precancerous and cancerous processes, it may indicate treatment with a broad-spectrum antibiotic for [[streptococci]] and [[anaerobic bacteria]] (such as [[metronidazole]] and [[amoxicillin]]) before repeating the smear. Alternatively, the test will be repeated at an earlier time than it would otherwise.<ref name=Hughey>[http://www.ttuhsc.edu/elpaso/som/obgyn/obgyn101/my%20documents4/Text/Pap/coccoid_bacteria.htm OB-GYN 101: Introductory Obstetrics & Gynecology > Coccoid Bacteria] {{Webarchive|url=https://web.archive.org/web/20140222013237/http://www.ttuhsc.edu/elpaso/som/obgyn/obgyn101/my%20documents4/Text/Pap/coccoid_bacteria.htm |date=2014-02-22 }} by Michael Hughey Hughey at [[Texas Tech University Health Sciences Center]]. Retrieved Feb 2014.</ref> If there are symptoms of [[vaginal discharge]], bad odor or irritation, the presence of coccoid bacteria also may indicate treatment with antibiotics as per above.<ref name=Hughey/>

==References==
;Notes
{{Reflist|30em}}

==External links==
{{Sister project links|b=no|n=no|q=no|species=no|voy=no|wikt=no|s=no|v=no|commons=Category:Pap test}}
* [http://www.cancer.gov/cancertopics/factsheet/Detection/Pap-test The Pap Test: Questions and Answers]&nbsp;— from the U.S.'s [[National Cancer Institute]]
* [https://web.archive.org/web/20060221194840/http://medlineplus.nlm.nih.gov/medlineplus/cervicalcancer.html#preventionscreening MedlinePlus: Cervical Cancer Prevention/Screening]&nbsp;— from [[MedlinePlus]]
* [http://www.cancerscreening.nhs.uk/cervical/index.html NHS Cervical Screening Programme]&nbsp;— from the UK's [[National Health Service]]
* [http://www.cancerresearchuk.org/cancer-help/type/cervical-cancer/about/cervical-cancer-screening Cervical cancer screening information]&nbsp;– from [[Cancer Research UK]]
* [http://labtestsonline.org/understanding/analytes/pap/tab/test Pap Smear]&nbsp;– from Lab Tests Online
* [https://web.archive.org/web/20081120034246/http://www.emedicinehealth.com/articles/12373-1.asp Pap Smear]&nbsp;— from eMedicineHealth
* [http://www.papscreen.org.au/ PapScreen]&nbsp;– Australian information about Pap tests (or Pap smears)
* [https://web.archive.org/web/20070208035246/http://www.hpvinfo.ca/hpvinfo/professionals/guidelines.aspx Canadian Guidelines for Cervical Cancer Screening]&nbsp;– [[Society of Obstetricians and Gynaecologists of Canada]]

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{{Human papillomavirus}}
{{Genital procedures}}

{{DEFAULTSORT:Pap Test}}
[[Category:Cytopathology]]
[[Category:Diagnostic obstetrics and gynaecology]]
[[Category:Greek inventions]]
[[Category:Cervical cancer]]
[[Category:Infectious causes of cancer]]
[[Category:Medical tests]]
[[Category:Papillomavirus-associated diseases]]