Cut-off Values for Biomarkers. A Review of Statistical Methods and an Application Study on the Association Between UTI and CRP in Febrile Seizure

Dichotomizing continuous biomarkers is a widely used technique in statistical and medical research (especially those regarding the relationship between continuous covariate and outcome). There are many methods in literature to determinate the optimal cut-off point value of a continuous biomarker. The present research describes methods based on (i) minimum p-value, (ii) AUC, sensitivity and specificity and (iii) decision tree. As application in this study, the results of Youden index, closest to (0,1), concordance probability and decision tree methods are used for estimating the optimal cut-off value of CRP for differentiating between without UTI and UTI in children with febrile seizure.