Statistical analysis
After the SBRs of all sampling sites were calculated using the method mentioned in the previous study8, a receiver operating characteristic (ROC) curve for SBRs of fluorescence colposcopy was drawn by a custom-written Matlab (MathWorks, the United States) code, and the cut-off value was set at the maximum of Euclidean’s index. SBR greater than the cut-off value was considered a positive examination result. When analyzing on the per-patient basis, we took the sampling site with the highest SBR value for each patient as the measurement index.
The diagnostic efficiency according to the patient and the sampling point respectively were calculate by comparing the results of the colposcopy with the pathological diagnosis. The indicators of diagnostic efficiency included accuracy, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and associated 95% confidence intervals (CI). To compare the diagnostic efficiency of fluorescence colposcopy and conventional colposcopy, chi-square test or Fisher’s exact test were performed by IBM SPSS statistics 22. Differences were considered to be statistically significant at P<0.05.