Validation of the AD-CSF-index in autopsy-confirmed Alzheimer's disease patients and healthy controls

J Alzheimers Dis. 2014;41(3):903-9. doi: 10.3233/JAD-131085.


The cerebrospinal fluid (CSF) biomarkers amyloid-β peptide of 42 amino acids (Aβ1-42), total tau-protein (T-tau), and tau phosphorylated at threonine 181 (P-tau181P) are used to diagnose Alzheimer's disease (AD). In order to increase diagnostic power, several biomarker combinations have been proposed. In that sense, a new CSF biomarker index was developed, the AD-CSF-index, which has been validated in clinically diagnosed AD patients using electrochemoluminescence based Meso Scale Discovery and single-analyte ELISA kits. This study validated the AD-CSF-index in neuropathologically diagnosed AD patients, using both single-analyte ELISA and multi-analyte Luminex assays. CSF of 51 neuropathologically diagnosed AD patients and of 95 controls was analyzed by commercially available single-analyte ELISA-kits (INNOTEST, Innogenetics) and by a Research Use Only version of the multi-analyte Luminex xMAP assay (INNO-BIA AlzBio3, Innogenetics). Subsequently the AD-CSF-indices were calculated. Both T-tau and P-tau181P AD-CSF-indices were significantly increased in AD patients when compared to controls (p < 0.001). The diagnostic power of the indices was calculated using ROC analyses, resulting in excellent sensitivity and specificity values that systematically exceeded the 80% threshold for discriminating autopsy-confirmed AD patients from controls, independent of the analytical platform. The power to discriminate between AD and non-AD dementias was not included in this study and should be validated in the future. In conclusion, this study validated the AD-CSF-index in autopsy-confirmed AD patients and has shown that its excellent diagnostic accuracy is independent of the analytical platform.

Keywords: Alzheimer's disease; biomarkers; cerebrospinal fluid; diagnostic accuracy; sensitivity; specificity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Alzheimer Disease / cerebrospinal fluid*
  • Alzheimer Disease / pathology*
  • Amyloid beta-Peptides / cerebrospinal fluid*
  • Autopsy / methods*
  • Enzyme-Linked Immunosorbent Assay
  • Female
  • Humans
  • Male
  • Middle Aged
  • Psychiatric Status Rating Scales
  • ROC Curve
  • Sensitivity and Specificity
  • tau Proteins / cerebrospinal fluid*


  • Amyloid beta-Peptides
  • tau Proteins