GAP43 and epilepsy: As regards the performance characteristics of GAP-43 in diagnosing epilepsy at cut-off point ≤ 0.6 ng/mL showed 78% sensitivity, 62% specificity, positive predictive value (PPV) = 50.6%, negative predictive value (NPP) = 84.9% with AUC = 0.574 (Table 4 and Fig. 2).