CSF levels of Aβ1-42, tau and p-tau can discriminate Alzheimer disease patients from controls or from patients with other types of dementia, and can identify incipient AD among patients with mild cognitive impairment (Hansson et al., 2006; Blennow et al., 2003). However, large differences are reported in absolute biomarker levels between centers (Sunderland et al., 2003), making it difficult to set up multi-center studies including multicenter treatment trials. To overcome this problem, external quality control assessment schemes (EQAS) are needed (Libeer et al., 2001). Our study describes the first worldwide EQAS for CSF biomarkers (20 different centres measured the same CSF samples), reporting relatively high inter-center variations, especially for Aβ1-42 (>22 percent). Lower inter-center variability (  Read more

CSF levels of Aβ1-42, tau and p-tau can discriminate Alzheimer disease patients from controls or from patients with other types of dementia, and can identify incipient AD among patients with mild cognitive impairment (Hansson et al., 2006; Blennow et al., 2003). However, large differences are reported in absolute biomarker levels between centers (Sunderland et al., 2003), making it difficult to set up multi-center studies including multicenter treatment trials. To overcome this problem, external quality control assessment schemes (EQAS) are needed (Libeer et al., 2001). Our study describes the first worldwide EQAS for CSF biomarkers (20 different centres measured the same CSF samples), reporting relatively high inter-center variations, especially for Aβ1-42 (>22 percent). Lower inter-center variability (<10 percent) is required to reliably distinguish a difference in group, to make multicenter biomarker comparisons possible, and eventually to obtain an inter-center reference range for AD.

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