A Study of Quality Control in Pap Smear Cytology in a Tertiary Care Centre Using ASC:SIL Ratio

Abstract

Introduction: Internal quality indicators used in gynecological cytopathology include determining the rate of atypical squamous cells (ASC), calculation of ASC: SIL ratio, cytologyhistology correlation, and high-risk HPV-positivity rates in ASC-US. These indicators help in quality control measures. Bethesda suggests that the ASC: SIL ratio should be less than 3:1. this study aims to determine the ASC: SIL ratio as an internal quality control indicator in gynecological cytological smears.

Material and Methods: The present study was conducted in the Department of Pathology SRMS Institute of Medical Sciences, Bareilly, UP. Archived cases of the preceding 2 years, from January 1, 2023, to December 31, 2024, were taken. The clinical details were retrieved from records. The study included conventional pap-stained smears of ASC-US, ASC-H, LSIL, HSIL, and SCC. ASC: SIL ratio was calculated by dividing the Sum of all ASC cases by the Sum of all SIL cases.

Results: About 5231 cervical Pap smears were received during the study period, of which 5061 (97%) were satisfactory. There were 39 cases with squamous cell abnormality, of which 13 were ASCUS, 9 were ASC-H, 8 were HSIL, 3 were LSIL, 6 were SCC cases, and the ratio ASC: SIL was 1.28, which was below the upper benchmark of 3:1.

Conclusion: The ASC: SIL ratio is a simple method for calculating internal quality indicators in cervical cytopathology. Keeping it below 3:1 reduces diagnostic uncertainty and supports WHO’s goal to eliminate cervical cancer. Regular feedback and periodic training programs can help reduce the ASC: SIL ratio, which exceeds the benchmark of 3:1.