Quality‐assurance study of simultaneously sampled, non‐correlating cervical cytology and biopsies

As part of a quality assurance study, we reviewed 223 cases of simultaneously sampled cervical smears and biopsies that showed a significant lack of correlation for squamous dysplasia or carcinoma. In 153 of the 223 cases (68.6%), the cytology was negative and the biopsy positive. After review of the specimens, errors in this group were found to be of the following types: sampling 64%, interpretive 29%, and combined sampling and interpretive 7%. In the remaining 70 cases (31.4%), the biopsy was negative and the Papanicolaou smear positive. In these cases, the following types of errors occurred: sampling 54%, interpretive 33%, and combination 13%. Twenty‐nine of these 70 patients showed dysplasia on follow‐up material. These findings indicate there are a significant number of false‐negative Papanicolaou smears, mostly because of sampling problems. There are few false‐positives. In cases of positive Papanicolaou and negative biopsy, dysplasia is likely to be present in subsequent samples.