A comparison of modified MonoPrep2 of liquid-based cytology with ThinPrep Pap test

The purpose of this study is to evaluate a modified MonoPrep2 (MP) of liquid-based cytology (LBC) to search for a less expensive alternative technique usable for screening of cervical cancers.

Cervicovaginal direct-to-vial samples from 1218 consecutive patients were processed with the modified MP technique and the results were compared with those of currently popular ThinPrep Pap test (TP) technique.

Both MP and TP methods provide uniformly spread thin layers of cells without cellular overlap or significant obscuring elements. The diameter of the circular area was 20 mm in MP and 22 mm in TP. Obscuring factors were slightly more frequent in MP but not enough to affect interpretation. Thirteen specimens were excluded from the study because of poor specimen quality in MP. In 1205 patients, there was an absolute agreement in results (the Bethesda diagnosis system) between the two methods, and discordances were observed in only 18 (1.5%) in 1187 cases (98.5%). Furthermore, there was no significant difference in diagnostic accuracy in histopathologic correlation between the two methods. The sensitivity of MP was slightly lower than that of TP, and the specificity of MP was higher than that of TP. A human papillomavirus (HPV) test with polymerase chain reaction (PCR) using broad-spectrum probes has yielded good results in both MP and TP samples.

The modification of the MP method gave comparable results to those of TP in terms of smear quality, cytologic diagnostic evaluation, and biopsy correlation with much less cost. The modified MP offers a cost-effective alternative to the currently popular expensive techniques of liquid-based cytology practical for cervical cancer screening.