CSF tau protein andβ‐amyloid (1–42) in Alzheimer's disease diagnosis: discrimination from normal ageing and other dementias in the Greek population

Abstract

Cerebrospinal fluid (CSF) levels of tau protein and amyloid beta(1-42) peptide (Abeta42) have been suggested as possible diagnostic markers of Alzheimer's disease (AD). In order to evaluate their diagnostic potential in clinical practice, we measured tau and Abeta42 levels in the CSF of 49 AD patients, 15 patients with non-AD neurodegenerative dementias (NAND), six patients with vascular dementia (VD) and 49 elderly controls. All the subjects were of Greek origin. A marked increase in tau, a decrease in Abeta42 and a marked increase in the tau/Abeta42 ratio was noted in AD. Abeta42 alone had a specificity of 80% and a sensitivity of 82% in differentiating AD from normal ageing, whilst the corresponding values for differentiating AD from NAND or VD were 80 and 71, or 67 and 82%, respectively. Tau was better in differentiating AD, from normal ageing (specificity 96%, sensitivity 88%), NAND (specificity 93%, sensitivity 71%) and VD (specificity 83%, sensitivity 94%). The tau/Abeta42 ratio achieved values comparable or even better than tau for differentiating AD from normal ageing (specificity 86%, sensitivity 96%) and VD (specificity 83%, sensitivity 90%) and definitely better than any of the candidate markers alone, for differentiating AD from NAND (specificity 100%, sensitivity 71%). Thus, the combined use of CSF tau and Abeta42 in the form of the tau/Abeta42 ratio is a simple, safe and useful adjuvant to clinical criteria for dementia diagnosis.

Amyloid-β(1–42), Total Tau, and Phosphorylated Tau as Cerebrospinal Fluid Biomarkers for the Diagnosis of Alzheimer Disease

“…When the concentration of 1 analyte is increased and that of the other is decreased, a ratio might be more informative (12,26,27 ). When results of biomarker measurements are clearly method dependent, as is the case with CSF biomarkers, calculation of a ratio has only local value and is not useful for comparison with other studies.…”

Cerebrospinal fluid protein biomarkers for Alzheimer’s disease

“…61 The 20 largest studies 14,20,24,41,50,56,[62][63][64][65][66][67][68][69][70][71][72][73][74][75] including more than 2000 AD patients and 1000 controls, evaluating the most commonly used ELISA method for T-tau in CSF, 14 are summarized in Table 2. The mean sensitivity to discriminate AD from nondemented aged individuals has been 81%, at a specificity level of 91% (Table 2).…”

Alzheimer’s Diseases: Towards Biomarkers for an Early Diagnosis

“…Using of ratio T-tau/A 42 increases the diagnosis specificity of AD compared with control subjects and other degenerative dementias (Gomez-Tortosa, Gonzalo et al 2003;Kapaki, Paraskevas et al 2003). Specificity of this ratio in differentiation of AD from vascular dementias is higher than 80% nevertheless this ratio is less efficient for differentiating AD and DLB (Gomez-Tortosa, Gonzalo et al 2003).…”