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Table 2 Diagnostic performance of individual and combined models in detecting Aβ-PET positivity at Youden’s cutoff

From: Plasma Aβ42/40 ratio alone or combined with FDG-PET can accurately predict amyloid-PET positivity: a cross-sectional analysis from the AB255 Study

  Sensitivity Specificity PPV NPV LR+ LR−
Whole population (N = 59)
 TP42/40 0.778 0.875 0.732 0.900 6.22 0.25
 Age+APOE4+Clinical Group 0.944 0.805 0.680 0.945 4.84 0.07
 TP42/40+Age+APOE4+Clinical Group 0.944 0.925 0.847 0.974 12.59 0.06
 AD-Conv score 1.000 0.675 0.706 1.000 3.08 0.00
 AdjustedTP42/40+AD-Conv score 1.000 0.923 0.851 1.000 13.00 0.00
Only CN (N = 39)
 TP42/40 1.000 0.886 0.500 1.000 8.75 0.00
 Age+APOE4 0.750 0.943 0.600 0.971 12.12 0.26
 TP42/40+Age+APOE4 1.000 1.000 1.000 1.000 0.00
 AD-Conv score 1.000 0.765 0.327 1.000 4.25 0.00
 AdjustedTP42/40+AD-Conv score 1.000 1.000 1.000 1.000 0.00
Only a-MCI (N = 20)
 TP42/40 0.714 1.000 1.000 0.653 0.29
 Age+APOE4 0.357 0.833 0.799 0.411 2.14 0.77
 TP42/40+Age+APOE4 0.643 1.000 1.000 0.601 0.36
 AD-Conv score 0.846 0.500 0.759 0.636 1.70 0.31
 AdjustedTP42/40+AD-Conv score 0.615 1.000 1.000 0.583 0.38
  1. Cases in which LR+ was not quantifiable were presented as –. Prevalence considered for each group calculation was corresponding to the present cohort: 30.5% in the whole population, 10.25% in the CN group, and 65% in the a-MCI group. PET PPV-positive predictive value, NPV negative predictive value, LR+ positive likelihood ratio, LR− negative likelihood ratio