AbstractThe aim of this study is to perform the synthesis and evaluation of the new near-infrared targeting fluorescent dye folic acid-ZW800-1 (ZW-FA) and to explore its potential feasibility for in vitro diagnosis of endometrial cancer. Characterisation and Folate receptor-α (FR-α) targeting verification of ZW-FA were performed first and 92 patients were recruited, after liquid-based cytology preparations, during a 15-month period. ZW-FA and Hematoxylin-Eosin (H&E) staining were performed on all cytological slides successively; the histological diagnoses were regarded as the gold standard for ROC curve analysis. The cut-off value of ZW-FA fluorescence intensity is 62.9745; the sensitivity (Se), specificity (Sp), false-negative rate (FNR), false-positive rate (FPR), positive predictive value (PV+) percentage and negative predictive value (PV–) of the ZW-FA method are 84.6%, 85.2%, 15.4%,14.8%, 93.2% and 69.7%, respectively. ZW-FA is potentially efficient for in vitro diagnosis of endometrial lesions based on the FR-α expression level of different endometrial lesions.