Published: 2017-08-26

Implications of inter observer variability in cervical smear reporting

. Sushma, Roshny Jacob


Background: In spite of the Bethesda system 2001 (TBS 2001), formulating strict guidelines for reporting cervical smears, intra observer and inter observer variations are unavoidable and can be considered an inherent part of the reporting system. The implications of this variation are in the quality of performance of the reporting laboratory and in the patient management. Rescreening is a tool to reduce the variations and improve the quality of both the laboratory staff and laboratory as such. Rescreening by two or more experienced observers has helped in identifying new cases better. The present study aims to rescreen cervical smears by two independent observers, to compare the results of the two independent observers and to understand the implications of this variability on the quality of cervical smear reporting.

Methods: 1000 consecutive cervical smears were rescreened by two experienced cyto-pathologists independently. Their findings were charted out and analyzed statistically for kappa value.

Results: Initial reporting had identified 20 cases of neoplastic nature. First observer identified, in addition, 6 new cases and second observer identified 12 new cases. The inter observer variability of 6 cases showed a kappa value of 0.89.

Conclusions: Rescreening is a safe way of picking up missed cases. Rescreening by two or more observers is better in identifying new cases. This helps in improving the quality of reporting personnel and the laboratory as well as in improving patient care.


Cervical smear, Inter observer variability, Kappa value, Rescreening

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Papanicolaou GN, Traut HF. The diagnostic value of vaginal smears in carcinoma of the uterus. Am J Obstetrics Gynecol. 1941;42:193.

Solomon D, Nayar R, Eds. The Bethesda System for Reporting Cervical Cytology. 2nd ed. New York: Springer-Verlag; 2004:1-192.

Klinkhamer PJ, Vooijs GP, De Haan AF. Interobserver and interobserver variability in the diagnosis of epithelial abnormalities in cervical smears. Acta Cytol. 1988;32(6):794-800.

Gupta DK, Komaromy-Hiller G, Raab SS, Nath ME. Interobserver and interobserver variability in the cytologic diagnosis of normal and abnormal metaplastic squamous cells in pap smears. Acta Cytol. 2001;45(5):697-703.

Tobias AHG, Amaral RG, Diniz EM, Carneiro CM. Quality indicators of cervical cytopathology tests in the public service in Minas Gerais, Brazil. Rev Bras Ginecol Obstet. 2016;38(2):065-70.

Balulescu I, Badea M. Inter observer variability in the interpretation of cervical smears-a must for developing an internal laboratory quality control system. Ginecoeu. 2011;9(34):178-83.

Arbyn M, Anttila A, Jordan J, Ronco G, Schenck U, Segnan N, et al. European guidelines for quality assurance in cervical cancer screening. second edition-summary document. Ann Oncol. 2010;21(3):448-58.

Young NA, Naryshkin S, Atkinson BF, Ehya H, Gupta PK, Kline TS, Luff RD. Interobserver variability of cervical smears with squamous-cell abnormalities: a Philadelphia study. Diagn Cytopathol. 1994;11(4):352-7.

Mwaniki JN, Waweru W, Ndungu JR, Muchiri LW. A retrospective study on interobserver variation of Pap smear reporting at Kenyatta national hospital (KNH) cytology laboratory, Nairobi, Kenya. Pathol. 2014;46:S63-4.

Siddegowda RB, DivyaRani MN, Natarajan M, Biligi DS. Inter-observer variation in reporting of pap smears. National J Laboratory Med. 2016;5(3):22-5.

Stoler MH, Schiffman M. Interobserver variability of cervical cytologic and histologic interpretations: realistic estimates from the ASCUS-LSIL Triage Study. JAMA. 2011;285(11):1500-5.

Bigras G, Wilson J, Russell L, Johnson G, Morel D, Saddik M. Interobserver concordance in the assessment of features used for the diagnosis of cervical atypical squamous cells and squamous intraepithelial lesions (ASC-US, ASC-H, LSIL and HSIL). Cytopathol. 2013;24(1):44-51.

Gatscha RM, Abadi M, Babore S, Chhieng D, Miller MJ. Smears diagnosed as ASCUS: Interobserver variation and follow-up. Diagnostic Cytopathol. 2001;25(2):138-40.

La Ruche G, Mensah-Ado I, Bergeron C, Welffens-Ekra C, Dabis F. Cervical screening in Africa: discordant diagnosis in a double independent reading. DYSCER-CI Group. J Clin Epidemiol. 1999;52(10):953-8.

Chhieng DC, Talley LI, Roberson J, Gatscha RM, Jhala NC, Elgert PA. Interobserver variability- comparison between liquid-based and conventional preparations in gynecologic cytology. Cancer Cytopathol. 2002;96(2):67-73.

Turkmen IC, Bassullu N, Bingol B, Dogusoy GB, Arici S. Interobserver variability in cervical smears from patients with a history of abnormal cytology: comparison of conventional pap smears and liquid-based cytology. Erciyes Med J. 2013;35(1):13-7.

Lee JD, Oh YH, Lee SO, Kim JY. Comparison of diagnostic cytomorphology of atypical squamous cells in liquid-based preparations and conventional smears. Korean J Pathol. 2012;46:365-9.

Doornewaard H, Van der Schouw YT, Van der Graaf Y, Bos AB, Van den Tweel JG. Observer variation in cytologic grading for cervical dysplasia of Papanicolaou smears with the PAPNET testing system. Cancer. 1999;87(4):178-83.