Does the time of day or weekday affect screening accuracy?

Abstract

Workload is extensively regulated in gynecologic cytology. However, sensitive monitors of excessive workload are not available. We measured the variation in abnormal (atypical squamous cells [ASC], low-grade squamous intraepithelial lesion [LSIL], and high-grade squamous intraepithelial lesion [HSIL]) rates for 4 cytotechnologists (CTs) among different days of the week and at different times during the day while they were performing primary screening with the ThinPrep Imaging System. Three of 4 CTs detected significantly less abnormal cases on 1 day of the week than another (1 Monday, 2 Friday). Two of those CTs detected significantly fewer total abnormal cases in the afternoon than in the morning; this was strongly correlated with increased speed in the afternoon and decreased detection of ASC cases. HPV + rates for ASC cases dropped as the abnormal rate dropped. The third CT detected significantly fewer ASC cases in the morning; this was counterbalanced by an increase detection of LSIL cases, suggesting a shift in diagnostic threshold between the AM and PM. The difference in abnormal detection rates between morning and afternoon correlated with a false-negative fraction of 0.96. There are significant differences in detection rates of abnormal cases between days of the week and the morning and afternoon. Correlating abnormal rates and workload between the morning and afternoon may represent a sensitive way to detect excessive workload. Because individual CTs may have different responses to workload and no overall pattern emerged, data on their workload and performance need to be tracked individually.