. 2018 Sep 21;91(3):291–300.

Table 1. Performance of AD biomarkers.

Biomarker		Sensitivity / Specificity	References
CSF	Aβ_1-42	0.86/ 0.90	[7]
	Aβ_1-42/Aβ_1-40	0.93/ 1.0	[8]
	p-tau	0.80/ 0.92	[7]
	t-tau	0.81/ 0.90	[7]
Plasma	Aβ_1-42	0.93/ 0.96	[9]
	Aβ_1-42/ Aβ_1-40	0.90/ 0.90	[10]
	APP_669-711/A_1-42	0.85/ 0.95	[10]
	Composite	0.95/ 0.95	[10]
PET	Aβ	0.85/ 0.88	[11]
	Tau	0.93-0.97/ 1.0	[12]
	FDG	0.84/ 0.86	[11]
MRI		0.81/ 0.75	[11]

Sensitivity and specificity figures for AD biomarkers, for the comparison AD dementia versus controls. Though these are in line with recommendations by the 1998 Biomarker Working Group, stating that an ideal AD biomarker should have sensitivity and specificity > 80% [13], performance is imperfect; this relates to the use of patients possibly misdiagnosed or harbouring mixed pathologies, the use of amyloid-positive “controls” and the high overlap in pathology between AD and other dementia disorders. Composite = APP_669–711/Aβ_1-42 to Aβ_1-40/Aβ_1-42.