SPP1 and Alzheimer disease: Whereas the majority of these biomarkers are unlikely to have diagnostic utility individually as they have lower sensitivity/specificity than T-Tau/β-amyloid 1–42 ratio or P-Tau, MDH, YKL-40 and osteopontin were individually capable of differentiating AD from non-AD CSF with AUC⩾0.75; and collectively all five of the 'validated' biomarkers could distinguish individuals with AD-positive/negative CSF with AUC=0.88.