Inflammatory atypia and the false-negative smear in cervical intraepithelial neoplasia

The effectiveness of cervical cytologic screening is compromised by the increasingly recognized prevalence of false-negative smears. Our previous studies suggested that some false-negative cytologies can be accounted for by smears showing cervical intraepithelial neoplasia (CIN) reported as inflammatory atypia; we found that at least 4% of 5,752 consecutive smears had been underreported in this manner. In the present study, that data was reanalyzed to derive 95% confidence limits for the number of CIN smears reported as inflammatory atypia. Using several differing estimates of cytologic screening sensitivity, it is speculated that, under certain testable assumptions, colposcopy of patients with cytologic diagnoses of inflammatory atypia may be one cost-effective approach to finding CIN cases missed by screening. If confirmed, these findings imply that laboratory quality assurance efforts, traditionally directed to the most serious cytologic diagnoses, should also focus in part on nondysplastic atypia.