Partial re-screening of all negative smears. A method of quality control of pathology department concerning smear screening against cervix cancer
Jensen, M.L.; Dybdahl, H.; Svanholm, H.
Ugeskrift for Laeger 162(21): 3024-3027
2000
ISSN/ISBN: 0041-5782 PMID: 10850190 Document Number: 265373
Partial rescreening of all negative smears is recommended as the most cost-effective method of internal quality control. The method was tested by eight cytotechnologists and the average diagnostic sensitivity, assessed upon their answering of 200 test-smears (150 negative and 50 positive) was 80%, while specificity vas calculated to 95%. Partial rescreening has here-upon been used in daily routine. After one year 21,000 smears have been re-screened. Twenty-nine cases of false negatives, 16 with atypia, eight with koilocytosis, and five cases with dysplasia have been detected, which corresponds to an overall false negative rate on 3%. In five of the 29 false negative cases with dysplasia histological follow-up has shown three cases of CIN III (two carcinoma in situ, one severe dysplasia), one case with CIN II (moderate dysplasia) and one case with CIN I (mild dysplasia). Conclusively, partial rescreening of all negative smears implies an improved quality with reduction of the number of false negative specimens.