An Analysis of Quality Control in Pap Cytology in A Tertiary Care Centre By Using ASC to SIL Ratio

Abstract

Background : Atypical Squamous Cells (ASC) is a common gynaecological cytologic abnormality, comprising around 5% of Papanicolaou test results. It reflects a diagnosis of uncertainty and is used as an intra-laboratory & inter-laboratory comparison tool for quality control purposes. For this purpose, ASC/SIL ratio can be used as a quality control measure. Bethesda system suggests that ASC/SIL ratio for an individual or laboratory should be less than 2:1 or 3:1. Objectives :To assess the ratio of ASC/SIL categories and thereby evaluation of quality control in gynaecological cytology smears. Methods : The present study being a retrospective study was conducted in the Dept. of Pathology, ESIC Medical College& Postgraduate Institute of Medical Sciences and Research, (ESIC MC & PGIMSR), Rajajinagar, Bangalore. Archived cases of preceding 5 years from Jan 2012 to Nov 2016 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. A total of 436 cases were studied. ASC/SIL ratio was calculated. ASC component included ASC-US and ASC-H. SIL component included LSIL, HSIL and SCC. Results : Of the total 436 cases, 226 cases were ASCUS and ASC-H and 210 cases were LSIL,HSIL and SCC. ASC/SIL ratio was obtained by dividing the sum of all ASC cases by the sum of all SIL cases. The ratio obtained was 1.1:1 which is below the upper bench mark of 3:1. Conclusion : Monitoring the ASC/SIL ratio of a laboratory is a useful quality control measure.Bethesda system have suggested that the ratio should be less than 3 and others have suggested that lower ratios are desirable. As diagnosis of ASCUS conveys uncertainty, a low ratio decreases the uncertainty produced by laboratory and may reduce the percentage of women with negative biopsy results. DOI: 10.21276/APALM.1421