Tau/Aß42
Also known as: Alzheimer biomarkers
Formal name: Tau protein and Amyloid Beta 42 peptide
Related tests: Phosporylated Tau (P-tau), Apolipoprotein E genotyping (ApoE), Presenilin 1 (PSEN1)
The Test Sample
What is being tested?
Amyloid beta 42 is a peptide that can undergo increased production resulting in a collection of senile plaques in the brain. Tau is a structural protein of the brain that, when changed chemically (becomes saturated with phosphorus groups, P-tau), can create neurofibrillary tangles, twisted protein fragments that develop in neurons that disrupt their ability to transport signals. These tangles in conjunction with the plaques are considered to be the main diagnostic features of Alzheimer's Disease (AD) at autopsy. The measurement of tau and Aß42 in CSF is being evaluated for potential roles in the diagnosis and monitoring of AD. It has been shown that a decrease in Aß42 with elevated tau or P-tau levels may predict the onset of AD.
How is the sample collected for testing?
Cerebrospinal fluid samples are collected using a lumbar puncture (spinal tap) procedure. This procedure is usually done in a hospital or clinic.
NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.
Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.
Is any test preparation needed to ensure the quality of the sample?
Your physician will advise you of any preparatory requirements. This is not a blood test but one on spinal fluid. Lumbar punctures are usually done in a hospital setting.
