BACKGROUND: The false-negative rate (FNR), or fraction, of Papanicolaou (Pap) smear screening has been proposed as a useful quality assessment measure. The FNR should account for the FNR of the rescreening process itself. The authors measured the FNR of the rescreening process by rescreening a set of abnormal smears. METHODS: A randomly selected group of negative (150) and abnormal (91) smears were rescreened in a blinded fashion. A diagnosis of atypical squamous cells of undetermined significance (ASCUS) or worse was used as a positive (abnormal) result. All discrepancies were confirmed by consensus review. The true FNR of screening Pap smears was calculated as: true FNR = calculated FNR/(1-FNR of rescreening). RESULTS: When rescreened, 17 originally negative cases were interpreted as ASCUS and 5 as unsatisfactory. Twenty-three originally abnormal cases (22 ASCUS and 1 low grade squamous intraepithelial lesion) were interpreted as negative. After consensus review, only 1 of the originally negative cases was believed to be ASCUS and 1 unsatisfactory; 18 of the 23 originally abnormal cases were believed to be rescreening errors and 5 of the 23 originally abnormal cases were believed to be false-positives. The FNR of Pap smear screening as traditionally calculated was 6.1%, which was slightly less than the laboratory's usual FNR. The FNR of review screening was 20.9%. The true FNR of Pap smear screening was 7.8% and the false-positive rate was 0.6%. CONCLUSIONS: The FNR of rescreening is not insubstantial. It can and should be measured by rescreening abnormal smears, and when taken into account yields a more accurate measure of the FNR of Pap smear screening.
BACKGROUND: The false-negative rate (FNR), or fraction, of Papanicolaou (Pap) smear screening has been proposed as a useful quality assessment measure. The FNR should account for the FNR of the rescreening process itself. The authors measured the FNR of the rescreening process by rescreening a set of abnormal smears. METHODS: A randomly selected group of negative (150) and abnormal (91) smears were rescreened in a blinded fashion. A diagnosis of atypical squamous cells of undetermined significance (ASCUS) or worse was used as a positive (abnormal) result. All discrepancies were confirmed by consensus review. The true FNR of screening Pap smears was calculated as: true FNR = calculated FNR/(1-FNR of rescreening). RESULTS: When rescreened, 17 originally negative cases were interpreted as ASCUS and 5 as unsatisfactory. Twenty-three originally abnormal cases (22 ASCUS and 1 low grade squamous intraepithelial lesion) were interpreted as negative. After consensus review, only 1 of the originally negative cases was believed to be ASCUS and 1 unsatisfactory; 18 of the 23 originally abnormal cases were believed to be rescreening errors and 5 of the 23 originally abnormal cases were believed to be false-positives. The FNR of Pap smear screening as traditionally calculated was 6.1%, which was slightly less than the laboratory's usual FNR. The FNR of review screening was 20.9%. The true FNR of Pap smear screening was 7.8% and the false-positive rate was 0.6%. CONCLUSIONS: The FNR of rescreening is not insubstantial. It can and should be measured by rescreening abnormal smears, and when taken into account yields a more accurate measure of the FNR of Pap smear screening.
Authors: Prakash K Bhuyan; Michael Dallas; Kim Kraynyak; Timothy Herring; Matthew Morrow; Jean Boyer; Susan Duff; Joseph Kim; David B Weiner Journal: Hum Vaccin Immunother Date: 2020-11-11 Impact factor: 3.452