Liquid-Based Cervical Cytology: Monitoring the Laboratory Quality Indicators

Many developments in cervical cancer screening have happened in the past century, helping women in earlier detection of cervical cancer and its precursors. Cytology still holds the fort as being a specific test, though it suffers in sensitivity. As a part of the quality control program, the aim of the study is to determine the total number of abnormal liquid-based cervical cytology (LBC) at our center and correlate the abnormal LBC with histology and human papillomavirus (HPV) DNA test results.

Retrospective analysis of 4286 LBC screening cases was carried out over a period of 5 years. For cytology-histology correlation, cervical biopsy and cytology test results were analyzed. The two-tier grading system for biopsy interpretation was used. HPV DNA test results wherever available were correlated.

Of the 4286 LBC cases, 157 samples (3.7%) were unsatisfactory for evaluation, 3915 samples (91.3%) were negative for intra-epithelial lesion or malignancy, and 214 samples (5%) showed epithelial cell abnormality. ASC-US was reported in 60 cases (1.4%), ASC-H in 35 cases (0.8%), LSIL in 47 cases (1.1%), HSIL in 41 cases (1.0%), squamous cell carcinoma in a single case (0.02%), and atypical glandular cells in 30 cases (0.7%). The ASC/SIL ratio was 1.07:1. The CHC major discrepancy was calculated as 16.2%. The concordance of HSIL on cytology and biopsy as a measure of PPV is 94.4%. Of the epithelial cell abnormalities, 24 cases were positive for high-risk HPV (hrHPV). Molecular test results of 2737 samples showed HPV detected in 50 cases, of which 24 cases were positive for hrHPV.

The study helped us to analyze the quality parameters of our cytopathology laboratory which are within the acceptable limits.