Objective To compare the accuracy of liquid based cytology using the computerised ThinPrep Imager with that of manually read conventional cytology.Design Prospective study.Setting Pathology laboratory in Sydney, Australia.Participants 55 164 split sample pairs (liquid based sample collected after conventional sample from one collection) from consecutive samples of women choosing both types of cytology and whose specimens were examined between August 2004 and June 2005.Main outcome measures Primary outcome was accuracy of slides for detecting squamous lesions. Secondary outcomes were rate of unsatisfactory slides, distribution of squamous cytological classifications, and accuracy of detecting glandular lesions.Results Fewer unsatisfactory slides were found for imager read cytology than for conventional cytology (1.8% v 3.1%; P<0.001). More slides were classified as abnormal by imager read cytology (7.4% v 6.0% overall and 2.8% v 2.2% for cervical intraepithelial neoplasia of grade 1 or higher). Among 550 patients in whom imager read cytology was cervical intraepithelial neoplasia grade 1 or higher and conventional cytology was less severe than grade 1, 133 of 380 biopsy samples taken were high grade histology. Among 294 patients in whom imager read cytology was less severe than cervical intraepithelial neoplasia grade 1 and conventional cytology was grade 1 or higher, 62 of 210 biopsy samples taken were high grade histology. Imager read cytology therefore detected 71 more cases of high grade histology than did conventional cytology, resulting from 170 more biopsies. Similar results were found when one pathologist reread the slides, masked to cytology results.Conclusion The ThinPrep Imager detects 1.29 more cases of histological high grade squamous disease per 1000 women screened than conventional cytology, with cervical intraepithelial neoplasia grade 1 as the threshold for referral to colposcopy. More imager read slides than conventional slides were satisfactory for examination and more contained low grade cytological abnormalities. INTRODUCTIONAlthough manual checking of conventional cervical smears has been used for decades to screen for cervical cancer and precancerous cells, liquid based cytology is replacing conventional cytology in many countries. The potential advantages of liquid based cytology are adjunctive testing, including testing for human papillomavirus; faster reading times; and cost saving of automation. Evidence is insufficient, however, to confirm that liquid based cytology is more accurate than conventional cytology, 1 which continues to be widely used.Conventional cytology involves the transference of cervical material from a collection instrument on to a glass slide whereas liquid based cytology (for example, the ThinPrep Liquid-based Cytology Preparation system, Cytyc, Marlborough, MA) involves rinsing the collection instrument in liquid to produce a suspension, which is processed in a laboratory to produce a monolayer of cells. The ThinPrep Imager (Cytyc) system, a computerised sy...
We aimed to compare the times cytologists spend reviewing cervical cytology slides processed by the ThinPrep Imager (TPI) with times they spend examining conventional cytology (CC) slides. We also aimed to examine the effect of cytologists' experience on reading times. Using a cross-sectional analytical design, we analyzed routine laboratory data, collected retrospectively over 7 months, for 41 cytologists, including paired data for 20 who read both TPI and CC slides. For the 20 cytologists who read both types of cytology, the mean reading rate was 13.3 slides per hour for TPI slides and 6.1 slides per hour for CC slides. The mean within-reader difference between TPI and CC rates was 7.2 slides per hour (P < 0.001). For CC reading, mean times did not differ between those who were additionally trained to read TPI slides and those who only read CC. Slower readers had greater increases in speed when using the TPI compared with CC reading than did faster readers (P < 0.001). More experienced cytologists tended to read CC slides more quickly than did those less experienced, but experience did not affect TPI reading times or within-reader differences in reading times between cytology types. The TPI significantly reduced reading times compared with CC. This reduction was greater amongst slower readers, and was unrelated to experience.
The authors set out to compare spending priorities for health care, across a selection of largely middle-income countries, through a survey of current and future decision makers.
Douglass Hanly Moir is a large Australian laboratory which has recently introduced the ThinPrep Imaging System (TPI) for reading ThinPrep slides, which is still performed using a split-sample technique. The Imager is a computerized system which identifies 22 fields for the cytologist to review using automated light microscopy. We compared the accuracy of TPI and conventional cytology (CC) during normal laboratory operation. The ThinPrep sample was prepared after taking a conventional Pap smear. TPI and CC reading was done without knowledge of the result of the other reading. The final cytology report issued to the referring doctor reflected the more severe of these two results. Histology results for all cases in which TPI and CC cytology results showed more than minimal disagreement were sought from the NSW Pap Test Register. Of 55 164 split sample pairs, 3.1% of CC of slides and 1.8% of TPI slides were unsatisfactory. There were 1758 women for whom there was more than minimal discrepancy between TPI and CC cytology results. TPI gave the more severe result in 1193 of the 1758 cases. In cases where only one of each pair of discrepant cytology results was CIN1 or higher grade, TPI detected 133 cases of high-grade histology among 380 biopsies (35%), whereas CC detected 62 cases among 210 biopsies (29.5%). A repeat analysis based on reading of histology by one pathologist blinded to initial Pap smear result showed a similar result. Reading times were measured over 5 months for both TPI and CC for twenty cytologists who read both types of smears. On average, they read 13.3 TPI slides per hour and 6.1 CC slides per hour. This study provides evidence that cervical cytology read using the TPI detects more histological high-grade disease than does CC. Further evidence shows that reading times are significantly reduced for cytologists using the TPI.Participation in External Quality Assessment (EQA) is a requirement of NHS CSP laboratories. As highlighted by the 1998 NHS executive letter, its principal function is educational with identification of poor performance likely to be exceptional. In 2003, NHS CSP published a protocol for laboratories in England for the EQA Scheme in Gynaecological Cytology, piloted in Trent and developed in line with RCPath recommendations. In Scotland and Northern Ireland, however, a different EQA system has evolved. Building on existing independent schemes, we have developed an integrated, comprehensive national programme of EQA, with three components designed to address three fundamental aspects: external assessment of smear reporting, continuing education in cervical cytology and evaluation of laboratory technical quality. The Interpretive Assessment component measures reporting performance by regularly testing individuals. Although recognised as one method of demonstrating competence, testing, scoring and assessment methods require sensitive interpretation. The Slide Circulation component is educational, providing regular exposure to, and discussion of, slides that are interesting or challen...
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