Alzheimer’s-Positive?

Making progress toward a blood test

By Quinn Eastman

Blood samples and a lab report

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Scientists have taken a step toward developing a long-sought blood test for Alzheimer’s, finding a group of markers that hold up in statistical analyses in three independent groups of patients, according to a study published online and in the journal Neurology.

“Reliability and failure to replicate initial results have been the biggest challenges in this field,” says lead author William Hu, assistant professor of neurology at Emory’s School of Medicine. “We demonstrate here that it is possible to show consistent findings.”

Hu and collaborators at the University of Pennsylvania and Washington University in St. Louis measured the levels of 190 proteins in the blood of six hundred study participants at those institutions. Participants included healthy volunteers and those who had been diagnosed with Alzheimer’s disease or mild cognitive impairment (MCI), often considered a harbinger of Alzheimer’s disease.

A subset of the 190 protein levels (seventeen) were significantly different in people with MCI or Alzheimer’s. When those markers were checked against data from 566 participants in the multicenter Alzheimer’s Disease Neuroimaging Initiative, only four markers remained.

“Though a blood test to identify underlying Alzheimer’s disease is not quite ready for prime time, we now have identified ways to make sure that a test will be reliable,” says Hu, who began the research while a fellow at the University of Pennsylvania. “In the meantime, the combination of a clinical exam and cerebrospinal fluid analysis remains the best tool for diagnosis in someone with mild memory or cognitive troubles.”

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