Performance characteristics of rapid (30-second) prescreening. Implications for calculating the false-negative rate and comparison with other quality assurance techniques.
Rapid (30-second) prescreening of cervicovaginal smears can be used to detect false-negative cases and determine the false-negative rate of primary screening, but the performance characteristics have not been evaluated fully. A test set of 242 cases including 80 originally false-negative cases were rapidly screened by 4 different cytotechnologists on 2 occasions. Intraobserver and interobserver reproducibility were good. Median specificity for each round of observations was 89% (range, 30%-96%). Median sensitivity for all true-positive cases was 78% (range, 63%-97%); for all false-negative cases it was 59% (range, 38%-89%). The relative sensitivity of rapid screening for true-positive and false-negative cases varied with the diagnosis. Rapid screening detected almost the same percentage of false-negative cases of atypical squamous cells of uncertain significance (ASCUS) as true-positive ASCUS cases (median ratio, 1.12; range, 0.72-1.52). The median ratio of false-negative to true-positive ASCUS cases was significantly different than the ratio for low-grade plus high-grade squamous intraepithelial lesions (0.68; range, 0.50-0.96). Although performance varies between individuals, in this test population the reproducibility, specificity, and sensitivity were good. Because it detects more false-negative cases at a lower cost per case than routine rescreening, rapid prescreening should be considered as an alternative to current quality control measures.
Renshaw
A A
AA
Division of Cytology, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.
Cronin
J A
JA
Minter
L J
LJ
Nappi
D
D
Whitman
T
T
Jiroutek
M
M
Cibas
E S
ES
D005188:False Negative Reactions; D005260:Female; D006801:Humans; D015588:Observer Variation; D011786:Quality Control; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D002583:Uterine Cervical Neoplasms / Q000175:diagnosis; D014626:Vaginal Smears; D002578:Uterine Cervical Dysplasia / Q000175:diagnosis