Official reprint from UpToDate®
www.uptodate.com ©2016 UpToDate®

Cervical and vaginal cytology: Interpretation of results (Pap test report)

Christopher P Crum, MD
Warner K Huh, MD
Section Editor
Barbara Goff, MD
Deputy Editor
Sandy J Falk, MD, FACOG


Cervical cytology became the standard screening test for cervical cancer and premalignant cervical lesions with the introduction of the Papanicolaou (Pap) smear in 1941 [1]. Liquid-based, thin layer preparation of cervical cytology specimens was a subsequent modification in technique. Terminology for reporting cervical cytology was standardized by the Bethesda System in 1988 [2]. This system has been revised several times, and the current system was developed in 2014 (table 1) [3-6]. Human papillomavirus (HPV) testing has now been incorporated into cervical cancer screening. (See "Screening for cervical cancer" and "Cervical cancer screening tests: Techniques for cervical cytology and human papillomavirus testing".)

The cervical cytology report is presented in a standard format. Interpretation of cervical cytology results will be reviewed here. Cervical cancer screening strategies and techniques, as well as the follow-up of abnormal cytology results and treatment of cervical intraepithelial neoplasia (CIN), are reviewed separately:

(See "Screening for cervical cancer".)

(See "Cervical cancer screening tests: Techniques for cervical cytology and human papillomavirus testing".)

(See "Cervical cytology: Evaluation of atypical squamous cells (ASC-US and ASC-H)".)


Subscribers log in here

To continue reading this article, you must log in with your personal, hospital, or group practice subscription. For more information or to purchase a personal subscription, click below on the option that best describes you:
Literature review current through: Sep 2016. | This topic last updated: May 31, 2016.
The content on the UpToDate website is not intended nor recommended as a substitute for medical advice, diagnosis, or treatment. Always seek the advice of your own physician or other qualified health care professional regarding any medical questions or conditions. The use of this website is governed by the UpToDate Terms of Use ©2016 UpToDate, Inc.
  1. Papanicolaou GN, Traut HF. The diagnostic value of vaginal smears in carcinoma of the uterus. Am J Obstet Gynecol 1941; 42:193.
  2. The 1988 Bethesda System for reporting cervical/vaginal cytological diagnoses. National Cancer Institute Workshop. JAMA 1989; 262:931.
  3. Broder S. From the National Institutes of Health. JAMA 1992; 267:1892.
  4. Solomon D, Davey D, Kurman R, et al. The 2001 Bethesda System: terminology for reporting results of cervical cytology. JAMA 2002; 287:2114.
  5. Nayar R, Wilbur DC. The Pap test and Bethesda 2014. Cancer Cytopathol 2015; 123:271.
  6. Nayar R, Wilbur DC. The Pap Test and Bethesda 2014: "The reports of my demise have been greatly exaggerated. (after a quotation from Mark Twain)". J Low Genit Tract Dis 2015; 19:175.
  7. Kurman R, Solomon D. The Bethesda System for Reporting Cervical/Vaginal Cytologic Diagnoses, Springer-Verlag, New York, NY 1994.
  8. Ho GY, Bierman R, Beardsley L, et al. Natural history of cervicovaginal papillomavirus infection in young women. N Engl J Med 1998; 338:423.
  9. Waxman AG, Chelmow D, Darragh TM, et al. Revised terminology for cervical histopathology and its implications for management of high-grade squamous intraepithelial lesions of the cervix. Obstet Gynecol 2012; 120:1465.
  10. Darragh TM, Colgan TJ, Thomas Cox J, et al. The Lower Anogenital Squamous Terminology Standardization project for HPV-associated lesions: background and consensus recommendations from the College of American Pathologists and the American Society for Colposcopy and Cervical Pathology. Int J Gynecol Pathol 2013; 32:76.
  11. Davey DD, Cox JT, Austin RM, et al. Cervical cytology specimen adequacy: patient management guidelines and optimizing specimen collection. J Low Genit Tract Dis 2008; 12:71.
  12. Joste N. Overview of the cytology laboratory: specimen processing through diagnosis. Obstet Gynecol Clin North Am 2008; 35:549.
  13. Massad LS, Einstein MH, Huh WK, et al. 2012 updated consensus guidelines for the management of abnormal cervical cancer screening tests and cancer precursors. J Low Genit Tract Dis 2013; 17:S1.
  14. Herfs M, Yamamoto Y, Laury A, et al. A discrete population of squamocolumnar junction cells implicated in the pathogenesis of cervical cancer. Proc Natl Acad Sci U S A 2012; 109:10516.
  15. Schiffman M, Castle PE, Jeronimo J, et al. Human papillomavirus and cervical cancer. Lancet 2007; 370:890.
  16. Baer A, Kiviat NB, Kulasingam S, et al. Liquid-based Papanicolaou smears without a transformation zone component: should clinicians worry? Obstet Gynecol 2002; 99:1053.
  17. Zhao C, Austin RM. Adjunctive high-risk human papillomavirus DNA testing is a useful option for disease risk assessment in patients with negative Papanicolaou tests without an endocervical/transformation zone sample. Cancer 2008; 114:242.
  18. Vooijs PG, Elias A, van der Graaf Y, Veling S. Relationship between the diagnosis of epithelial abnormalities and the composition of cervical smears. Acta Cytol 1985; 29:323.
  19. Kivlahan C, Ingram E. Papanicolaou smears without endocervical cells. Are they inadequate? Acta Cytol 1986; 30:258.
  20. Martin-Hirsch P, Lilford R, Jarvis G, Kitchener HC. Efficacy of cervical-smear collection devices: a systematic review and meta-analysis. Lancet 1999; 354:1763.
  21. Mitchell HS. Longitudinal analysis of histologic high-grade disease after negative cervical cytology according to endocervical status. Cancer 2001; 93:237.
  22. Mitchell H, Medley G. Longitudinal study of women with negative cervical smears according to endocervical status. Lancet 1991; 337:265.
  23. Bos AB, van Ballegooijen M, van den Akker-van Marle ME, et al. Endocervical status is not predictive of the incidence of cervical cancer in the years after negative smears. Am J Clin Pathol 2001; 115:851.
  24. Tacken MA, Braspenning JC, Mulder J, et al. Loss to follow-up of cervical smears without endocervical columnar cells is not disturbing. Eur J Gynaecol Oncol 2006; 27:42.
  25. Smith HO, Tiffany MF, Qualls CR, Key CR. The rising incidence of adenocarcinoma relative to squamous cell carcinoma of the uterine cervix in the United States--a 24-year population-based study. Gynecol Oncol 2000; 78:97.
  26. Mitchell H, Hocking J, Saville M. Cervical cytology screening history of women diagnosed with adenocarcinoma in situ of the cervix: a case-control study. Acta Cytol 2004; 48:595.
  27. Castle PE, Wacholder S, Sherman ME, et al. Absolute risk of a subsequent abnormal pap among oncogenic human papillomavirus DNA-positive, cytologically negative women. Cancer 2002; 95:2145.
  28. Bansal M, Austin RM, Zhao C. High-risk HPV DNA detected in less than 2% of over 25,000 cytology negative imaged liquid-based Pap test samples from women 30 and older. Gynecol Oncol 2009; 115:257.
  29. Davey DD, Austin RM, Birdsong G, et al. ASCCP Patient Management Guidelines: Pap Test Specimen Adequacy and Quality Indicators. J Low Genit Tract Dis 2002; 6:195.
  30. Hock YL, Ramaiah S, Wall ES, et al. Outcome of women with inadequate cervical smears followed up for five years. J Clin Pathol 2003; 56:592.
  31. Ransdell JS, Davey DD, Zaleski S. Clinicopathologic correlation of the unsatisfactory Papanicolaou smear. Cancer 1997; 81:139.
  32. Adams AL, Gidley J, Roberson J, et al. Clinical significance of unsatisfactory conventional pap smears owing to inadequate squamous cellularity defined by the Bethesda 2001 criterion. Am J Clin Pathol 2005; 123:738.
  33. Moriarty AT, Clayton AC, Zaleski S, et al. Unsatisfactory reporting rates: 2006 practices of participants in the college of american pathologists interlaboratory comparison program in gynecologic cytology. Arch Pathol Lab Med 2009; 133:1912.
  34. Hoda RS, Loukeris K, Abdul-Karim FW. Gynecologic cytology on conventional and liquid-based preparations: a comprehensive review of similarities and differences. Diagn Cytopathol 2013; 41:257.
  35. Sherman ME, Solomon D, Schiffman M, ASCUS LSIL Triage Study Group. Qualification of ASCUS. A comparison of equivocal LSIL and equivocal HSIL cervical cytology in the ASCUS LSIL Triage Study. Am J Clin Pathol 2001; 116:386.
  36. Quddus MR, Sung CJ, Steinhoff MM, et al. Atypical squamous metaplastic cells: reproducibility, outcome, and diagnostic features on ThinPrep Pap test. Cancer 2001; 93:16.
  37. Sherman ME, Tabbara SO, Scott DR, et al. "ASCUS, rule out HSIL": cytologic features, histologic correlates, and human papillomavirus detection. Mod Pathol 1999; 12:335.
  38. Nasser SM, Cibas ES, Crum CP, Faquin WC. The significance of the Papanicolaou smear diagnosis of low-grade squamous intraepithelial lesion cannot exclude high-grade squamous intraepithelial lesion. Cancer 2003; 99:272.
  39. Alsharif M, Kjeldahl K, Curran C, et al. Clinical significance of the diagnosis of low-grade squamous intraepithelial lesion, cannot exclude high-grade squamous intraepithelial lesion. Cancer 2009; 117:92.
  40. Jones BA, Novis DA. Cervical biopsy-cytology correlation. A College of American Pathologists Q-Probes study of 22 439 correlations in 348 laboratories. Arch Pathol Lab Med 1996; 120:523.
  41. Thrall M, Kjeldahl K, Savik K, et al. Rate of endometrial adenocarcinoma in women screened before and after implementation of the Bethesda 2001 reporting system. Acta Cytol 2008; 52:1.
  42. Fadare O, Ghofrani M, Chacho MS, Parkash V. The significance of benign endometrial cells in cervicovaginal smears. Adv Anat Pathol 2005; 12:274.
  43. Canfell K, Kang YJ, Clements M, et al. Normal endometrial cells in cervical cytology: systematic review of prevalence and relation to significant endometrial pathology. J Med Screen 2008; 15:188.
  44. Vooijs GP, van der Graaf Y, Vooijs MA. The presence of endometrial cells in cervical smears in relation to the day of the menstrual cycle and the method of contraception. Acta Cytol 1987; 31:427.
  46. Aslan DL, Crapanzano JP, Harshan M, et al. The Bethesda System 2001 recommendation for reporting of benign appearing endometrial cells in Pap tests of women age 40 years and older leads to unwarranted surveillance when followed without clinical qualifiers. Gynecol Oncol 2007; 107:86.
  47. Bean SM, Connolly K, Roberson J, et al. Incidence and clinical significance of morphologically benign-appearing endometrial cells in patients age 40 years or older: the impact of the 2001 Bethesda System. Cancer 2006; 108:39.
  48. Greenspan DL, Cardillo M, Davey DD, et al. Endometrial cells in cervical cytology: review of cytological features and clinical assessment. J Low Genit Tract Dis 2006; 10:111.
  49. Thrall MJ, Kjeldahl KS, Savik K, et al. Significance of benign endometrial cells in papanicolaou tests from women aged >or=40 years. Cancer 2005; 105:207.
  50. Simsir A, Carter W, Elgert P, Cangiarella J. Reporting endometrial cells in women 40 years and older: assessing the clinical usefulness of Bethesda 2001. Am J Clin Pathol 2005; 123:571.
  51. Ashfaq R, Sharma S, Dulley T, et al. Clinical relevance of benign endometrial cells in postmenopausal women. Diagn Cytopathol 2001; 25:235.
  52. Chang A, Sandweiss L, Bose S. Cytologically benign endometrial cells in the papanicolaou smears of postmenopausal women. Gynecol Oncol 2001; 80:37.
  53. Beal HN, Stone J, Beckmann MJ, McAsey ME. Endometrial cells identified in cervical cytology in women > or = 40 years of age: criteria for appropriate endometrial evaluation. Am J Obstet Gynecol 2007; 196:568.e1.
  54. Moatamed NA, Le LT, Levin MR, et al. In Papanicolaou smears, benign appearing endometrial cells bear no significance in predicting uterine endometrial adenocarcinomas. Diagn Cytopathol 2013; 41:335.
  55. Zahn CM, Askew AW, Hall KL, Barth WH Jr. The significance of hyperkeratosis/parakeratosis on otherwise normal Papanicolaou smears. Am J Obstet Gynecol 2002; 187:997.
  56. Lara-Torre E, Pinkerton JS. Accuracy of detection of trichomonas vaginalis organisms on a liquid-based papanicolaou smear. Am J Obstet Gynecol 2003; 188:354.
  57. Peters N, Van Leeuwen AM, Pieters WJ, et al. Bacterial vaginosis is not important in the etiology of cervical neoplasia: a survey on women with dyskaryotic smears. Sex Transm Dis 1995; 22:296.
  58. Klomp JM, Boon ME, Van Haaften M, Heintz AP. Cytologically diagnosed Gardnerella vaginalis infection and cervical (pre)neoplasia as established in population-based cervical screening. Am J Obstet Gynecol 2008; 199:480.e1.
  59. Pandit AA, Klhilnani PH, Powar HS, et al. Value of Papanicolaou smear in detection of Chlamydia trachomatis infection. Diagn Cytopathol 1993; 9:164.
  60. Cecchini S, Iossa A, Ciatto S, et al. Colposcopic survey of Papanicolaou test-negative cases with hyperkeratosis or parakeratosis. Obstet Gynecol 1990; 76:857.
  61. Katki HA, Schiffman M, Castle PE, et al. Benchmarking CIN 3+ risk as the basis for incorporating HPV and Pap cotesting into cervical screening and management guidelines. J Low Genit Tract Dis 2013; 17:S28.
  62. Katki HA, Schiffman M, Castle PE, et al. Five-year risks of CIN 3+ and cervical cancer among women who test Pap-negative but are HPV-positive. J Low Genit Tract Dis 2013; 17:S56.
  63. Practice Bulletin No. 168: Cervical Cancer Screening and Prevention. Obstet Gynecol 2016; 128:e111.
  64. Cox JT, Castle PE, Behrens CM, et al. Comparison of cervical cancer screening strategies incorporating different combinations of cytology, HPV testing, and genotyping for HPV 16/18: results from the ATHENA HPV study. Am J Obstet Gynecol 2013; 208:184.e1.
  65. Kjær SK, Frederiksen K, Munk C, Iftner T. Long-term absolute risk of cervical intraepithelial neoplasia grade 3 or worse following human papillomavirus infection: role of persistence. J Natl Cancer Inst 2010; 102:1478.
  66. Pearce KF, Haefner HK, Sarwar SF, Nolan TE. Cytopathological findings on vaginal Papanicolaou smears after hysterectomy for benign gynecologic disease. N Engl J Med 1996; 335:1559.
  67. Committee on Practice Bulletins—Gynecology. ACOG Practice Bulletin Number 131: Screening for cervical cancer. Obstet Gynecol 2012; 120:1222.
  68. Tambouret R, Pitman MB, Bell DA. Benign glandular cells in posthysterectomy vaginal smears. Acta Cytol 1998; 42:1403.
  69. Khan MJ, Massad LS, Kinney W, et al. A common clinical dilemma: Management of abnormal vaginal cytology and human papillomavirus test results. Gynecol Oncol 2016; 141:364.