The accuracy and consistency of the cytologic classification of squamous lesions of the uterine cervix.

The slides of 60 cases of cervical lesions in the five categories of benign inflammatory change, mild to moderate dysplasia, severe dysplasia, squamous carcinoma in situ, and invasive squamous carcinoma were reviewed on two separate occasions by two cytopathologists, nine cytotechnologists, and four cytotechnology students. Their overall concurrence of the cytologic with the tissue diagnoses was 78 per cent and was slightly higher for the cytotechnology students than for the more experienced observers. In 44 per cent of the invasive carcinomas and in 38 per cent of carcinomas in situ, there was considerable disagreement between cytologic and tissue classification partly due to the presence of inadequate material on the cytologic slides which had been selected consecutively based on the subsequent tissue diagnosis. The pathologists reproduced their own cytologic classification within one category variance in 94 per cent of the cases as compared to 92 per cent for the cytotechnologist and 86 per cent for the students. The study emphasizes the need for evaluation of laboratory performance based on routine diagnostic material in considering the accuracy and reproducibility of the procedure and in establishing quality control programs.