Fig. 2.

Average heat maps for predicted Aβ positive status based on 1000 optimal decision trees. Algorithms generated using immediate recall test z-score and age without (A) or with (B) consideration of APOE ε4 status. Red indicates higher probability of Aβ positivity, blue indicates higher probability of Aβ negativity. The hatched red line indicates the threshold for a probability of >0.5 to be considered predicted positive; different probability thresholds can be applied as appropriate depending on the clinical context and available resources. Abbreviations: Aβ, amyloid β; APOE, apolipoprotein E