Assessment of manual workload limits in gynecologic cytology: reconciling data from 3 major prospective trials of automated screening devices.

Previous prospective studies have shown different results when comparing automated and manual screening of gynecologic cytology. The results of 3 large prospective studies were reviewed and relative sensitivity used as a gold standard. No significant differences could be shown in relative sensitivity between the ThinPrep Imaging System and the FocalPoint GS Imaging System (P > .05). When manual screening was restricted to less than 6 hours per day, 50 or fewer slides per day, and at least 6 minutes per slide (<10 slides/h), the relative sensitivity for automation was significantly lower for atypical squamous cells of undetermined significance and above (ASC+) (0.81; 95% confidence interval [CI], 0.79-0.83) than when manual screening was not restricted (1.07; 95% CI, 1.03-1.10). All 3 sites that screened 10 or more slides per hour manually had a relative sensitivity for automation that was significantly higher for high-grade squamous intraepithelial lesions and above (HSIL+) than for the remaining groups who screened less than 10 slides per hour (1.40 [95% CI, 1.22-1.60] vs 0.97 [95% CI, 0.95-1.00]). These results suggest that location finding of abnormalities (ASC+) may be more strongly associated with time spent screening per day, whereas classification/interpretation skills (HSIL+) may depend on time spent on an individual case. There is no evidence that automated screening devices are more sensitive than manual screening performed at lower well-defined workloads. More restricted workloads (≤41 slides/d, ≤4.5 h/d) for manual screening may perform significantly better than automated screening devices as measured by histologic cervical intraepithelial neoplasia 2 and above.