Analytical performance and clinical utility of the INNOTEST (R) PHOSPHO-TAU(181P) assay for discrimination between Alzheimer's disease and dementia with Lewy bodies

Background: Total tau (T-tau) and beta-amyloid((1-42)) (A
beta(1-42)) levels in cerebrospinal fluid (CSF) can differentiate
Alzheimer's disease (AD) from normal aging or depressive
pseudo-dementia. Differential diagnosis from dementia with Lewy
bodies (DLB) in clinical settings is difficult. Methods: The
analytical performance of the INNOTEST (R) PHOSPHO-TAU((181P))
assay was validated in terms of selectivity, sensitivity,
specificity, precision, robustness, and stability. Clinical utility
of the assay alone, or combined with T-tau and AP1-421 for
discrimination of AD (n=94) from patients suffering from DLB (n=60)
or from age-matched control subjects (CS) (n=60) was assessed in a
multicenter study. Results: CSF concentrations of tau
phosphorylated at threonine 181 (P-tau(181P)) in AD was
significantly higher than in DLB and CS. Discriminant analysis, a
classification tree, and logistic regression showed that
P-tau(181P) was the most statistically significant single variable
of the three biomarkers for discrimination between AD and DLB.
Conclusions: P-tau(181P) quantification is a robust and reliable
assay that may be useful in discriminating AD from DLB.