OBJECTIVES: The purpose of this study was to carry out systematic review of the literature and meta-analysis to evaluate the diagnostic utility of cerebrospinal fluid (CSF) levels of the 42 amino acid form of amyloid-b (Ab₋) as a biomarker for differentiating Alzheimer’s disease (AD) from non-AD dementia. METHODS: Design - Systematic literature review was used to evaluate the effectiveness of the Ab for the diagnosis of Alzheimer’s disease. The Scottish Intercollegiate Guidelines Network (SIGN) tool was used by two evaluators to evaluate independently the quality of the 15 studies.  Data sources - The literature review covered from October 27, 1946, to October 22, 2013, and searched eight domestic databases including Korea Med and international databases including Ovid-MEDLINE, EMBASE, and Cochrane Library. Eligibility criteria for selecting studies - Primary criteria for inclusion were valid studies on (i) patients with mild cognitive impairment with confirmed or suspected AD and non-AD dementia, and (ii) assessment of Ab₋levels using appropriate comparative tests. RESULTS: A total of 15 studies (15 diagnostic evaluation studies) were identified in which levels of CSF Ab₋ were assessed. Meta-analysis was performed on nine robust studies that compared confirmed AD with healthy individuals (n = 1587), 10 studies that compared AD with non-AD dementias (n = 860), and four studies that compared a-MCI (amnestic mild cognitive impairment) with na-MCI (non-amnestic mild cognitive impairment) subjects (n = 857). Overall, Ablevels were reduced in CSF from AD patients versus healthy controls or non-AD dementia. The effectiveness of this test was evaluated for diagnostic accuracy. Diagnostic accuracy for identifying AD by ELISA was high (pooled sensitivity, 0.772 (95% CI 0.747–0.796); pooled specificity, 0.732 (95% CI 0.699–0.762). CONCLUSIONS: Reduced CSF Ab levels are of potential utility in the differential diagnosis of AD versus non-AD dementias and healthy controls.