Inter-Observer Variation in Reporting of Pap Smears

Abstract

Introduction: The Papanicolaou smear is one of the most important tests in preventive health care which helps to identify women at risk of developing cervical cancer. The use of the test is increasing because of more awareness. But the validity of the test has always been questioned because reporting of Pap smears is known to have interobserver and intra-observer variation, which can affect the prognosis of the patients or sometimes create legal issues too. Aim: To assess the frequency of discordant diagnosis between the pathologists in reporting of conventional Pap smears using the Bethesda System of reporting. Materials and Methods: A total of 200 cases of Pap smears with each case having 2 slides (ectocervix and endocervix) which were received, are labelled and stained using Papanicolaou stain. The slides are reported by a pathologist using the Bethesda System of reporting Pap smears. The reported slides are then reviewed by the second pathologist with the same level of experience and again reported following the same protocols. For those cases which had disagreement, the reports were confirmed by biopsy. If the biopsy could not be obtained, opinion was taken from the senior pathologist whose report was considered as a tie breaker. Statistical Analysis: Statistical analysis was done using Kappa statistics for all cases which had epithelial cell abnormality. Results: Among 200 cases, 22 cases had epithelial cell abnormality. The degree of agreement between the results obtained in the first and second assessment between the observers was analysed, with the overall Kappa of 0.61, indicating a moderate agreement. Conclusion: Inter-observer variation is a common screening error in reporting of Pap smears. It is necessary to implicate corrective actions to reduce such error which ultimately helps in detecting the cervical lesions in its earliest, which in turn affects the prognosis of the patients.

Keywords

• cervical cancer
• cytology
• disagreement