ThinPrep Papanicolaou testing to reduce false-negative cervical cytology.

The false-negative Papanicolaou (Pap) smear is the major quality issue currently facing the practitioners of diagnostic cytology. Failure to detect cervical disease in women can be due either to sampling error or to screening error. Sampling errors account for the majority of false-negative Pap tests; the remainder are due to the cervical abnormality either not being detected or not being properly classified during microscopic screening. The ThinPrep Pap test was recently cleared by the United States Food and Drug Administration as significantly more effective than the conventional Pap smear and as a replacement for the conventional method of Pap smear preparation. The ThinPrep Pap test increases detection of squamous intraepithelial lesions and significantly improves specimen quality. These features of the ThinPrep Pap test also have a heretofore unreported direct effect on the false-negative rate of the Pap examination. In two recently conducted clinical trials, the ThinPrep test resulted in a significant reduction in the sampling false-negative rate in women undergoing routine Pap screening. In addition, screening false negatives, as expressed by the false-negative proportion, were reduced from 5.6% with the conventional Pap smear, to 2.2% with the ThinPrep Pap test. More high-grade squamous intraepithelial lesions were detected in the screening populations with the ThinPrep test. The ThinPrep Pap test improves the quality of cervical cancer screening through a reduction in false-negative Pap examinations. This improvement has important implications for women undergoing Pap screening and for those who practice gynecologic cytopathology.