Rapid screening: a comparative study.
Although rapid screening of negative and inadequate cervical smears is a quality assurance requirement for all UK laboratories, there has been little attempt to standardize the method and laboratories make use of a number of different techniques and times. The aim of this study was to assess the sensitivity of these various techniques by measuring their ability to pick out known false-negative smears. Completed questionnaires from 123 laboratories across England revealed that 52% of laboratories use a "step" technique, 19% use "turret", 15% use random paths and 34% attempt to rescreen the whole slide quickly. Twenty-two percent of laboratories use a mixture of techniques. Timings are also variable, with the majority of laboratories allowing screeners to review slides at a pace decided by themselves but usually between 1 and 2 min. The study involved 120 participants who performed a total of 24 000 rapid screens. The results showed that, of the 90 abnormal slides used in the study, 62 cases (69%) were identified as abnormal or needing review by more than 50% of participants. Overall rapid screening picked out 58% of high-grade squamous abnormalities, 59% of low-grade abnormalities and 72% of glandular lesions. Step screening performed best, followed by whole slide/random and then turret. One minute was the optimum time and there was a significant fall in performance once individuals attempted to rescreen large numbers (>50). The most significant finding was the marked variation in the performance of individuals using the same slide sets.
Dudding
N
N
Regional Cytology Training School, United Leeds Teaching Hospitals, Leeds, W Yorkshire LS1 3EX, UK.
Hewer
E M
EM
Lancucki
L
L
Rice
S
S
D003951:Diagnostic Errors / Q000706:statistics & numerical data; D005188:False Negative Reactions; D005260:Female; D006801:Humans; D009313:National Health Programs; D015588:Observer Variation; D015397:Program Evaluation; D011786:Quality Control; D012680:Sensitivity and Specificity; D013997:Time Factors; D002577:Uterine Cervical Diseases / Q000175:diagnosis*; D014626:Vaginal Smears / Q000592:standards*