Does total manual rescreening of negative pap tests screened by the ThinPrep imaging system add any value?

We compared the performance of utilizing the ThinPrep® Imaging System (TIS) according to the manufacturer's directions to screening with the TIS plus total manual rescreening in Pap tests that were initially diagnosed as NIL to determine whether manual rescreening decreases the false-negative rate for epithelial lesions. Three thousand three hundred forty cases were diagnosed as NIL on the 22 fields of view selected by the TIS and subsequently manually rescreened by the same cytotechnologist. Six hundred seventy-four cases were sent to a cytopathologist for final diagnosis based on review criteria. Biopsy follow-up and Human Papilloma Virus (HPV) test results were noted if available for cases with a diagnosis of ASCUS or above. Three thousand one hundred fifty-nine (94.6%) were confirmed NIL and 181 cases were diagnosed as abnormal on manual rescreen. There were 147 ASCUS, 6 ASCH, 9 AGC, 19 LSIL, and 0 HSIL cases. The overall false-negative rate of screening for atypia/SIL with the TIS was 5.4%. Of the 147 cases with HPV results, 43 (29%) were positive. Only 1 cervical intraepithelial neoplasia 2 was found on biopsy follow-up, in a case of ASCUS with a positive HPV. Based on our data, the TIS for screening of Pap tests is reliable in NIL cases as compared to total manual rescreening. The majority of the false-negative cases were diagnosed as ASCUS on subsequent review, with 0 HSIL cases. Our results confirm that the TIS is highly accurate in excluding HSIL, negating the need for total manual rescreening of NIL Pap tests.