Fig. 3

Assessment of model performance by LOO cross-validation of all data, and positive predictive value (PPV)/negative predictive value (NPV). a Estimation of model performance showed that the models performed with an accuracy of 0.63–0.80. DLDA had the highest combination of sensitivity, specificity, and accuracy (0.65, 0.95, 0.80, respectively). b ROC analysis demonstrated that the models had AUC of 0.68 (NSC) to 0.84 (DLDA). c Plot showing the PPV of all models across all possible prevalence. The blue region in the figure represents the range of IA prevalence reported in the current literature. The best performing model (DLDA) had the highest PPV, and cosine NN demonstrated the poorest PPV. d The DLDA model also had the best NPV, but only slightly better than that of the cosine NN, NSC, and SVM models