Table 3.

Cutoff scores and sensitivity/specificity values of cerebrospinal fluid biomarkers (Aβ_1–42, T-tau, and P-tau) and combinations (Aβ_1–42/tau ratios; pathologic signatures) discriminating patients with AD from controls, AD from cognitive impairment/dementia due to other etiologies, and MCI patients who progressed to dementia from stable cases of MCI

CSF biomarker	Cutoff	AD (n = 41) versus controls (n = 41)		AD (n = 41) versus non-AD (n = 35)		MCI-AD (n = 19) versus MCI-S (n = 49)
Sensitivity, %	Specificity, %	Sensitivity, %	Specificity, %	Sensitivity, %	Specificity, %
Aβ1–42	<416.0 pg/mL	83	70	83	54	79	42
Phosphorylated tau	>36.1 pg/mL	83	49	80	68	84	46
Total tau	>76.7 pg/mL	82	67	78	57	79	50
Aβ1–42/P-tau	<9.53	88	78	85	71	90	65
Aβ1–42/T-tau	<4.13	80	80	76	66	74	69
Pathologic signature 1	—	78	83	78	74	79	69
Pathologic signature 2	—	73	85	74	74	74	73

Abbreviations: Aβ_1–42, amyloid-beta peptide; T-tau, total tau; P-tau, ¹⁸¹Thr-phosphorylated-tau; AD, Alzheimer's disease; Non-AD, cognitive impairment or dementia due to other etiologies; MCI, mild cognitive impairment; CSF, cerebrospinal fluid; MCI-AD, MCI subjects who progressed to AD; MCI-S, stable cases of MCI (i.e., subjects who retained the MCI diagnosis on follow-up); pathologic signature 1, Aβ_1–42 <416.0 and Aβ_1–42/P-tau <9.53; pathologic signature 2, Aβ_1–42 <416.0 and Aβ_1–42/T-tau <4.13.