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.