A new blood test could allow doctors to detect Alzheimer's disease early in patients presenting with memory problems, according to US researchers. The test measures levels of a protein called tau, which accumulates in the brain and causes cell death. Scientists say it could be used in GP surgeries within five years.
In a study published in Nature Medicine, researchers at the University of California, San Francisco, found that tau levels were 3.5 times higher in people with Alzheimer's than in healthy individuals. The test can also distinguish Alzheimer's from frontotemporal dementia, a less common condition often misdiagnosed as Alzheimer's.
The study involved 362 people aged 58 to 70, including 56 with Alzheimer's, 47 with mild cognitive impairment (MCI), 190 with frontotemporal dementia, and 69 healthy controls. Blood levels of phosphorylated tau 181 (pTau181) were 8.4 pg/ml in Alzheimer's patients, compared to 3.7 pg/ml in those with MCI and 2.4 pg/ml in healthy people.
Senior author Professor Adam Boxer said the test could identify patients for clinical trials or new treatments. He added that it would be especially beneficial for those with MCI, who are at higher risk of developing Alzheimer's. Currently, there is no single test for dementia; diagnosis relies on assessments and brain scans.
