A combined blood test for cognitive decline has a 90% accuracy rate in determining whether memory loss is due to Alzheimer’s disease, a new study found.
In comparison, neurologists and other memory specialists correctly diagnosed Alzheimer’s in 73% of their cases. Primary care doctors had even less success, with only a 61% accuracy rate, according to the study.
One part of the blood test — called plasma phosphorylated tau 217, or p-tau217 for short — is one of several blood biomarkers scientists are evaluating for use in the diagnosis of mild cognitive impairment and early-stage Alzheimer’s disease.
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Research published in January found a similar p-tau217 test is up to 96% accurate in identifying elevated levels of beta-amyloid and up to 97% accurate in identifying tau. The presence of beta-amyloid and tau tangles in the brain are hallmark signs of Alzheimer’s disease.
“We’d love to have a blood test that can be used in a primary care physician’s office, functioning like a cholesterol test but for Alzheimer’s,” said Dr. Maria Carrillo, chief science officer of the Alzheimer’s Association.
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Once fully vetted, highly accurate blood tests could “change the game in the speed in which we can conduct Alzheimer’s trials and get to the next new medication,” she said. “These are absolutely transformational times.”
















