A meta-analysis has concluded that amyloid-beta1-42 in CSF is useful for discriminating Alzheimer’s disease from controls (Rosa et al. J Alzheimers Dis 2014; epublished January 21, 2014).

The review included prospective, retrospective, case-control and cross-sectional studies. Of 804 citations identified, 41 were included in the analysis.

The meta-analysis showed that the diagnostic odds ratio for amyloid-beta1-42 was 28.9. Sensitivity was 84.3%; specificity was 79.4%.

However, a separate study has cautioned that methods for collection, treatment, storage and analysis of CSF samples have not been standardized, which may result in high variability in biomarker levels (Babic et al. Transl Neurosci 2013;4:10.2478; free full text at www.ncbi.nlm.nih.gov/pmc/articles/PMC3873720/). They further noted that ELISA kits for amyloid-beta1-42 (and for t-tau) produced by different manufacturers will not have the same results and should not be used interchangeably.

Comment
Dr. Yves Bacher:  Biomarkers will probably become more and more useful in the case of early-onset dementia, strong familial history, MCI management and atypical presentations. But their usefulness in the wider middle-aged population is currently limited. There remains a need for caution, as stated in the paper by Babic et al.