Table 3.

Results of DeLong tests indicating discriminative power between distinct diagnostic categories

BM-based discrimination between	Selected CSF BM	Selected CSF and/or serum MA or MT	AUC	95% CI	S (%)	Sp (%)
Without MA-MT
AD and FTD	Aβ1–42/P-tau181P ratio*	N/A	0.81	0.73–0.90	66	85
AD and DLB/PDD	Aβ1–42, T-tau & P-tau181P	N/A	0.82a(a)	0.73–0.91	88	73
AD and CONTR	Aβ1–42/T-tau ratio*	N/A	0.88	0.75–1.00	89	82
AD versus non-AD	Aβ1–42, T-tau & P-tau181P	N/A	0.87a	0.80–0.94	90	76
With inclusion of MA-MT
AD and FTD	Aβ1–42/P-tau181P ratio*	CSF NA	0.85	0.78–0.93	69	90
AD and DLB/PDD	Aβ1–42, T-tau & P-tau181P N/A (without BM)	CSF & serum MHPG CSF & serum MHPG	0.99aa 0.98a	0.97–1.0 0.95–1.0	98 98	95 95
AD and CONTR	Aβ1–42/T-tau ratio*	CSF NA	0.94	0.88–1.0	89	92
AD versus non-AD	Aβ1–42, T-tau & P-tau181P	CSF NA & TRP and serum 5-HIAA	0.95a	0.91–0.99	97	82

NOTE. Optimal cutoff values were determined by maximizing the Youden's index. Superscript letters “a” added to the AUC values indicate statistical significance: ^aP < .005; ^aaP < .001. An asterisk indicates the inclusion of biomarker ratios rather than separate biomarker levels for comparisons between AD and both FTD and CONTR, as described earlier in Struyfs et al. [41].

Abbreviations: 5-HIAA, 5-hydroxyindoleacetic acid; Aβ_1–42, amyloid β peptide of 42 amino acids; AD, Alzheimer's disease; AUC, area under the curve; BM, biomarkers; CI, confidence interval; CONTR, controls; CSF, cerebrospinal fluid; DLB/PDD, dementia with Lewy bodies/Parkinson's disease dementia; FTD, frontotemporal dementia; MHPG, 3-methoxy-4-hydroxyphenylglycol; MA & MT, monoamines and metabolites; N/A, not applicable; NA, noradrenaline; P-tau_181P, tau phosphorylated at threonine 181; S, sensitivity; Sp, specificity; TRP, tryptophan; T-tau, total tau.