Apparently healthy, but diagnosed with Alzheimer's disease?

New criteria could lead to a diagnosis of dementia based on a simple blood test, even in the absence of obvious symptoms.

Determining whether a person has Alzheimer's disease usually requires a thorough diagnostic process. A doctor takes a patient's medical history, discusses symptoms, administers verbal and visual cognitive tests.

The patient may undergo a PET scan, an MRI scan. or a lumbar puncture – tests that detect the presence of two proteins in the brain, amyloid plaques and tau tangles, both associated with Alzheimer's disease.

All this could change dramatically if new criteria proposed by an Alzheimer's Association task force are widely adopted.

Its final recommendations, expected later this year , will accelerate a change already underway: from the definition of disease by symptoms and behavior to its purely biological definition — with biomarkers, substances present in the body that indicate disease.

The draft guidelines, Revised Criteria for the Diagnosis and Staging of Alzheimer's Disease, call for a simpler approach. This could mean a blood test to indicate the presence of amyloid. Such tests are already available in some clinics and doctors' offices.

“A person with an amyloid biomarker in the brain has the disease, regardless of whether they whether symptomatic or not. " said Dr. Clifford R. Jack Jr., task force chair and Alzheimer's disease researcher at the Mayo Clinic.

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