3.4 Diagnostic efficiency of the LFS system
Five indicators were included in the scoring system designed in this study. The Youden index of all points was calculated according to the sensitivity and specificity of each cutoff point determined by the ROC curve, and the maximum Youden index (≥6 points) was taken as the reference cutoff point (Table 4). The lesion tended to be malignant when the score was ≥6 points, while the lesion tended to be benign when the score was <6 points. The efficiency of the cutoff value of ≥6 points for the diagnosis of benign and malignant vocal cord leukoplakia was the highest. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy rates were 93.8%, 83.6%, 64.3%, 97.7%, and 86.0%, respectively.