Cerebrospinal fluid tau protein shows a better discrimination in young old (<70 years) than in old old patients with Alzheimer's disease compared with controls

Tau protein is consistently reported to be elevated in cerebrospinal fluid (CSF) of patients with Alzheimer's disease (AD). CSF tau alone, however, is not a clinically useful diagnostic marker due to its relatively low diagnostic specificity. Therefore, efforts are under way to combine tau measurements with other criteria in order to improve diagnostic applicability. We investigated whether age could serve as an useful criterion to increase diagnostic accuracy. CSF levels of tau were measured in young old (