Cerebrospinal Fluid Aβ42, Tau, and F2-Isoprostane Concentrations in Patients With Alzheimer Disease, Other Dementias, and in Age-Matched Controls

OBJECTIVE: To test the hypothesis that quantification of cerebrospinal fluid (CSF) F(2)-isoprostanes (F(2)-IsoPs), in vivo biomarkers of free radical damage, along with CSF Abeta(42) and tau levels improves laboratory diagnostic accuracy for Alzheimer disease (AD). PARTICIPANTS: Patients with probable AD (n = 19), dementias other than AD (n = 8), and age-matched controls (n = 10). MAIN OUTCOME MEASURES: Cerebrospinal fluid concentrations of Abeta(42) and tau were determined by a commercially available test (Athena Diagnostics, Worcester, Mass). Cerebrospinal fluid F(2)-IsoP levels were quantified by gas chromatography/mass spectrometry. RESULTS: Individuals were classified as AD or non-AD by a published method using CSF Abeta(42) and tau levels (95% sensitivity, 50% specificity), by CSF F(2)-IsoP levels greater than 25 pg/mL and Abeta(42) concentrations less than 1125 pg/mL (90% sensitivity, 83% specificity), and by combined analysis using CSF F(2)-IsoP, Abeta(42), and tau levels (84% sensitivity, 89% specificity). CONCLUSION: Cerebrospinal fluid F(2)-IsoP quantification may enhance the accuracy of the laboratory diagnosis of AD.