TABLE 2.

Diagnostic accuracy of the 4‐plex Aβ_{1‐42/1‐40} ratio, NfL, GFAP, p‐tau181, and optimal panel

Cohort 1
AD vs. FTD	n	AUC	95% CI	P‐value	Sensitivity	Specificity
Aβ1‐42/1‐40 ratio	40 vs 40	0.62	0.49–0.75	.065	0.38	0.95
NfL	40 vs 40	0.79	0.69–0.89	<.001	0.48	0.98
GFAP	40 vs 40	0.81	0.71–0.90	<.001	0.75	0.73
P‐tau181	36 vs 38	0.85	0.75–0.94	<.001	0.74	0.97
Panel (NfL, P‐tau181)	36 vs 38	0.94	0.87–1.00	<.001	0.87	1.00
AD vs. DLB
Aβ1‐42/1‐40 ratio	40 vs 40	0.60	0.47–0.73	.124	0.38	0.95
NfL	40 vs 40	0.50	0.37–0.64	.946	0.28	0.98
GFAP	40 vs 40	0.69	0.57–0.81	.004	0.50	0.85
P‐tau181	36 vs 37	0.75	0.63–0.87	<.001	0.54	0.97
Panel (NfL, GFAP, p‐tau181)	36 vs 37	0.88	0.80–0.96	<.001	0.84	0.81

Cohort 2
AD vs. FTD	n	AUC	95% CI	P‐value	Sensitivity	Specificity
Aβ1‐42/1‐40 ratio	38 vs 38	0.58	0.46–0.71	.205	0.63	0.55
NfL	38 vs 37	0.78	0.68–0.88	<.001	0.89	0.55
GFAP	37 vs 38	0.71	0.60–0.83	.001	0.45	0.95
P‐tau181	38 vs 38	0.71	0.59–0.83	.002	0.66	0.76
Panel (NfL, GFAP, p‐tau181)	37 vs 37	0.90	0.82–0.98	<.001	0.81	0.92
AD vs. DLB
Aβ1‐42/1‐40 ratio	38 vs 38	0.56	0.43–0.69	.372	0.29	0.90
NfL	38 vs 38	0.63	0.51–0.76	.045	0.55	0.71
GFAP	37 vs 38	0.65	0.52–0.77	.027	0.40	0.87
P‐tau181	38 vs 38	0.81	0.71–0.91	<.001	0.76	0.76
Panel (p‐tau181)	38 vs 37	0.81	0.71–0.91	<.001	0.76	0.76

Notes: The panels were selected with backward logistic regression based on Wald's statistics, among the plasma markers Aβ_{1‐42/1‐40}, NfL, GFAP, and p‐tau181. Sensitivity and specificity are at Youden's indices.

Abbreviations: Aβ, amyloid beta; AD, Alzheimer's disease; AUC, area under the curve; CI, confidence interval; DLB, dementia with Lewy bodies; FTD, frontotemporal dementia; GFAP, glial fibrillary acidic protein; NfL, neurofilament light; p‐tau181, phosphorylated tau 181.