The stepAIC further narrowed down the model to five biomarkers: “YARS2,” “PRL,” “ADAM10,” “NTS,” and “CTSS.” The leave‐one‐out cross‐validation yielded an average delirium status prediction accuracy of 0.80 (sensitivity = 0.75, specificity = 0.85), which confirms the excellent generalizability of the prediction power for this small set of five biomarkers. Here, CTSS is linked to delirium.