This study was designed to investigate the ability to use CSF ptau-231 levels to distinguish patients with AD from control subjects and from patients with other dementias.  CSF from 192 patients with a clinical diagnosis of AD, frontotemporal dementia, vascular dementia, Lewy body dementia, other neurological disorders and healthy controls were analyzed in the ptau-231 test.  Overall, the assay had sensitivity level of 90.2% and specificity of 80%.  The same patient samples analyzed for total tau gave an overall sensitivity of 81.3% and a specificity of 68.5%.  Clearly the ptau-231 assay is superior to the total tau assay.  Additionally, the ptau-231 assay results fulfill the core criteria of a useful biomarker of AD as outlined by the consensus report of the Working Group on Molecular and Biochemical Markers of AD.

This study reports on the ability of the CSF assay to distinguish between Alzheimer's disease and major depression.  The patient population consisted of 34 individuals with depression, 64 probable AD, 17 possible AD and 21 healthy control individuals. Sensitivity was calculated at 92% with a specificity of 85%.

This study examined the potential diagnostic value of the ptau-231 assay to differentiate Creutzfeldt-Jakob disease (CJD), a very rare brain disorder in humans,  from AD (note: CJD is the human form of what is popularly called in cattle, Mad Cow Disease).  When the ptau-231/total tau ratio was used, 95% of the cases were correctly identified, however p-tau-231 alone had less diagnostic value.  The reason for this is that ptau-231 is a specific marker for AD. As reported in this paper and other articles, up to 19% of CJD patients also have underlying AD pathology when examined by autopsy, close to the 23% reported here that have higher levels of ptau-231 and are presumed to have AD pathology. This study involved CSF from 21 patients with CJD, 37 patients with AD, and 10 healthy controls.

This manuscript describes CSF pTau231, isoprostane and Ab42/Ab40 levels in normal individuals and how the levels change with age and the presence of the ApoE4 allele.

This is an abstract of a poster presented at the European CSF symposium in 2000 by Harald Hampel.  The small study presented compares CSF biomarkers total tau, soluble gp130, neuronal thread protein, and ptau-231 in AD patients vs. healthy controls.  Of the biomarkers reported here, ptau-231 showed the best performance (100% sensitivity, 91.7% specificity).  Furthermore, levels of ptau-231 were correlated with AD progression and MCI individuals had elevated levels of ptau-231 indicative of AD.  It was concluded that ptau-231 might serve as a biomarker in the early detection of AD and in following disease progression in subjects at risk and in AD patients.

This study compares the performance of the ptau-231 assay with Innogenetics ptau-181 assay and Mitsubishi’s ptau-199 assay. The patient population consisted of 166 patients with a clinical diagnosis of AD, frontotemporal dementia (FTD), Lewy body dementia or vascular dementia and 45 nondemented controls.  To enable comparisons between the three assays sensitivity was set at 85% and the specificity of each assay was assessed.  When comparing AD samples to non-AD samples as a group, the APNS assay had a specificity of 85%, the Innogenetics assay had a specificity of 81% and the Mitsubishi assay had specificity between 61-72%.  When broken down by disease state (i.e. AD versus a specific type of dementia) the APNS assay demonstrated higher levels of sensitivity, especially when the AD vs. FTD catagory was analyzed, with the APNS assay having a sensitivity of 92%, while the sensitivities of the Innogenetics assay and the Mitsubishi assay were 79% and 42-54% respectively.

This is the first publication on the APNS CSF assay.  The first part of the paper describes the specificity of the antibodies (Tau-1, CP27, and CP9) as well as describing in detail the laboratory method and reagents used in the assay.  The second part of the paper documents a study which examined the ability of the assay to discriminate between AD and non-AD patients. CSF from 27 AD and 31 non-AD patients were analyzed with a resulting sensitivity of 85% and a specificity of 97%.