Biomarker Evaluation and Predictive Model

For each biomarker, the receiver operating characteristic curve was constructed and the AUC value was computed by numeric integration of the receiver operating characteristic curve. The logistic regression method was used for predicting the validity of the biomarker. For this model, the predicted probability for each subject was obtained and also was used to construct a receiver operating characteristic curve. The standard error of the AUC and the 95% CI for the receiver operating characteristic curves were computed and the sensitivity and specificity for each biomarker and for the biomarker combination were estimated by identifying the cut-off point of the predicted probability that yielded the highest sum of sensitivity and specificity.