AN EVALUATION OF RAPID REVIEW AS A METHOD OF QUALITY-CONTROL OF CERVICAL SMEARS USING THE AXIOHOME MICROSCOPE

One method of quality control which has recently been recommended by p rofessional bodies in the UK is the 'rapid review' method. This involv es the microscopic 30 s review of all negative cervical smears with th e intention of flagging potential missed abnormalities. Although it ha s been suggested that rapid review is better than 10% random rescreeni ng of negative smears, the efficiency and efficacy of this method of q uality control have not been thoroughly evaluated. We have used the Ax ioHOME system, which can record the area of a slide covered and the sc reening time, to investigate slide coverage during rapid review qualit y control, as performed by 15 cytoscreeners and MLSOs reviewing a test set of 22 slides each. The test set comprised 18 negative slides, thr ee positive slides, and one unsatisfactory slide. We have recorded two distinct methods of rapid review in use amongst cytotechnologists, th e step method and the whole slide method. The data show that rapid rev iew takes longer on average than the recommended 30 s, the mean screen ing times being 76 s and 82 s for the step and whole slide methods, re spectively. Abnormal smears were missed on three of 15 occasions by th e step method (sensitivity 80%, positive predictive value 85%), and on seven of 30 occasions by the whole slide method (sensitivity 76.6%, p ositive predictive value 45%). However, the 95% confidence intervals w ere wide (57.7-90.7% for the step method, and 51.9-95.7% for the whole slide method). Analysis of scanning tracks and screening rates shows significant flaws in the methodology of rapid review. Abnormal cells w ere not identified, although dyskaryotic cells were included in the sc anning track on nine occasions, seven using the whole slide method and two using the step method. On one occasion (using the step method) ab normal cells were not identified because they were not included in the scanning track. Further research is in progress to determine optimal methods of rapid review, and whether the rapid review technique is as effective as automated screening systems for quality assurance in cyto logy.