Screening for total Tau at the CSF is used to investigate Alzheimer's disease, in patients with memory loss and in brain injury investigations.
Tau proteins (the Greek letter T) are proteins that stabilize the microtubules in the cells. They are abundant in neurons of the central nervous system and are also found at very low levels in astrocytes and oligodendrocytes of the CNS. Pathological conditions of the nervous system, such as Alzheimer's disease, are related to Tau proteins that have become defective and do not properly stabilize the microtubules.
The measurement of total Tau protein reflects the destruction and degradation of the axons. Tau protein can be phosphorylated to varying degrees (Phospho-Tau). Measurement of total Tau is used as a biomarker for Alzheimer's disease, but elevated Tau levels may also be observed in other degenerative diseases of the central nervous system and in strokes. Higher Tau levels are observed in Creutzfeldt-Jakob disease with rapid progressive cortical degeneration.
- Alzheimer's disease: moderate to large increase in total Tau (sensitivity to Alzheimer's disease detection 85%)
- Extensive acute stroke: a sharp increase in total Tau
- Creutzfeldt-Jakob disease (CJD): a sharp increase in total Tau
- Frontal dementia: normal or slightly elevated levels of total Tau
- Lewy body dementia: normal or slightly elevated levels of total Tau
- Vascular dementia: normal or slightly elevated levels of total Tau
- Amyotrophic lateral sclerosis (ALS): normal levels of total Tau
Normal aging, mild cognitive impairment without progression to Alzheimer's disease, depression, Parkinson's disease, and non-acute cerebrovascular disease have normal levels of total Tau.
